Hanson  tJames  &radleit. 


f\  Study  of  Decom  position  Proce  sses 

Applicable  to  Certain  Products  of  Coal  Car bonizat,o 


n . 


' 


A STUDY  OF  DECOMPOSITION  PROCESSES 
APPLICABLE  TO  CERTAIN  PRODUCTS 
OF  COAL  CARBONIZATION 


BY 


MANSON  JAMES  BRADLEY 
A.  B.  McMaster  University,  1915 
A.  M.  McMaster  University,  1915 


THESIS 


Submitted  in  Partial  Fulfillment  of  the  Requirements  for  the 


Degree  of 


DOCTOR  OF  PHILOSOPHY 
IN  CHEMISTRY 


IN 


THE  GRADUATE  SCHOOL 

OF  THE 

UNIVERSITY  OF  ILLINOIS 


1921 


if 


University  of  Illinois  Library 


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and  Doctor’s  degrees  and  deposited  in  the  University 
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requires  also  the  consent  of  the  Dean  of  the  Graduate 
School  of  the  University  of  Illinois. 


has  been  used  by 

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tions. 

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This  Thesis 


s 


NAME  AND  ADDRESS 


DATE 


0':  , 





. 


21 

nz 


UNIVERSITY  OF  ILLINOIS 


THE  GRADUATE  SCHOOL 


May  10,  i9£1 


I HEREBY  RECOMMEND  THAT  THE  THESIS  PREPARED  UNDER  MY 

SUPERVISION  BY Mans  on  James  Bradley 

ENTITLED MA  Study  of  Decomposition  Processes  Applicable 

to  Certain  Products  of  Coal  Carbonization. ” 


BE  ACCEPTED  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR 


THE  DEGREE  of  Doctor  of  Philosophy  in  Chemistry 


IaT  Jl. 


In  Charge  of  Thesis 


Head  of  Department 


Recommendation  concurred  in* 


Committee 

on 

Final  Examination* 


*Required  for  doctor’s  degree  but  not  for  master’s 


Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/studyofdecomposiOObrad 


1. 


ACKbTOWLEDGSiUENT 

The  writer  wishes  to  express  his  sincere  thanks  to 
Prof.  S.W.  Parr,  whose  suggestions,  assistance,  guidance  and 
encouragement  made  this  thesis  possible.  Deep  appreciation  is 
felt  for  the  valuable  training  in  the  fundamentals  of  research. 
It  is  expected  that  this  stimulated  appreciation  of  chemical 
investigation  will  increase  with  time  because  research  is 
appreciati on . 

He  also  wishes  to  thank  Dr.  T.E.Layng,  not  only  for 
help  and  instruction  in  assemblying  the  apparatus,  but  more 
especially,  for  the  .many  valuable  suggestions  and  advice  during 
the  investigation. 


Table  of  Contents 


2. 


I.  INTRODUCTION. 

1.  Preliminary 

2.  General  Considerations. 

3.  Scope  of  Previous  Investigations 

4.  Outline  of  Present  Investigation 

5.  Grouping  of  results  of  the  Investigat ion . 

II.  EXPERIMENTAL  WORK. 

1.  Apparatus 

2.  Method  of  Operation 

3.  Method  of  Analysing  products 

4.  Specification  of  the  Hydrocarbons  used  in  the 
investigation. 

5.  Preliminary  Runs. 

6.  Series  of  Runs  using  Charcoal  surfaces. 

7.  Series  of  Runs  through  Iron  Furnace 

8.  Series  of  Runs  using  Copper  lining  in  the 
Furnace 

9.  Series  of  Runs  using  Tinned-Copper  Lining 
in  the  Furnace 

10.  Series  of  Runs  using  Refractory  Lining  in 
the  Furnace. 

11.  Series  of  Runs  using  Benzene 

12.  Series  of  Runs  using  Toluene 

13.  Series  of  Runs  using  Naphthalene. 

III.  SOME  PRODUCTS  SYNTHESISED  IN  THE  INVESTIGATION. 

1.  Gases,  2 Liquids,  3 Solids. 

IV.  SUMMARY. 

V.  BIBLIOGRAPHY 


3 

4 

10 

15 

17 

19 

21 

22 

23 

23 

25 

37 

42 

50 

62 

73 

73 

74 

76 

63 

85 


VI  . VITA. 


66 


3. 


A STUDY  OF  DECOMPOSITION  PROCESSES  APPLICABLE  TO 
CERTAIN  PRODUCTS  OF  COAL  CARBONIZATION. 

1.  INTRODUCTION. 


I.  PRELIMINARY. 

In  undertaking  a complex  investigation  such  as  that  of 
the  reactions  occuring  during  the  decomposition  of  the  products 
of  coal  carbonization,  there  are  two  principal  procedures  to 
follow.  One  might  take  the  crude  material  in  all  its  complexity, 
decompose  it  under  diversified  conditi ons , and, by  the  careful 
examination  of  accurately  recorded  result s , endeavor  to  arrive  at 
definite  conclusions,  the  validity  of  which  could  be  established 
by  further  observati on , or  by  modifying  details  in  the  direction 
indicated.  This  is  the  intelligent  and  progressive  practice  fol- 
lowed by  industrial  concerns.  Alternatively,  one  might  try  to 
arrive  at  a better  understand! ng  of  the  intricate  complex  by  a 
preliminary  study  of  single  c onsti tuent s , determining,  for 
example,  the  mode  of  formation  and  decomposition  of  some  one 
constituent  of  coal  carbonization  under  a variety  of  conditions, 
including,  as  of  primary  importance,  those  conditions  to  which 
it  would  be  subjected  in  carbonizing  practice.  This  method  is 
particularly  suited  to  the  laboratory  and  is  the  principle 
underlying  the  following  investigation.  Even  the  study  of 
the  decomposition  of  a single  constituent  becomes  very  complex 
when  we  take  into  consideration,  the  factors  that  influence 
equilibrium  in  any  gaseous  chemical  reaction.  Among  these 
factors,  temperature,  pressure,  concentration  or  mass  action, 


4 


duration  of  time  of  contact  or  reaction,  and  contact  surfaces 
are  of  prime  importance.  Several  of  these  factors,  such  as 
temperature  control,  may  he  suh-divided  into  a number  of 
problems,  each  of  which  may  be  very  difficult  of  solution, 
especially  if  it  is  desired  to  construct  large  scale  apparatus 
for  the  commercial  production  of  these  decomposition  products. 

2.  GENERAL  CONSIDERATIONS. 

True  equilibrium,  that  state  in  which  reactions  pro- 
ceed equally  in  each  direction,  is  seldom  attained  in  any 
hydrocarbon  decomposition.  Under  constant  pressure  there  is 
a definite  proportion,  of  the  individual  constituents  for  each 
temperature;  under  constant  temperature  there  is  a definite 
proportion  between  the  reacting  constituents  for  each  pre  s- 
sure,  even  if  the  numerical  value  of  the  equilibrium 
constant  is  a function  only  of  temperature.  Heat  can  supply 
the  energy  necessary  to  change  an  existing  state  of  chemi- 
cal inertia  and  cause  reaction  between  the  various  molecu- 
lar formations  but  too  high  a temperature,  during  an  extend- 
ed period  of  time,  permits  the  hydrocarbon  to  decompose  into 

carbon  and  permanent  gases.  The  father  the  system  is  from 

* 

stable  equilibrium  the  greater  the  tendency  for  reaction  to 
take  place.  Changing  the  temperature  may  bring  the  system 
nearer  to  the  desired  equilibrium  point.  No  single  equili- 
brium, however,  can  be  considered  by  itself  because  all  the 
constituents  must  also  be  in  equilibrium,  or  a system  of 


5. 


equilibria  between  all  the  components  of  the  system.  In 
an  unbalanced  system  of  gases  there  is  a tendency  for  an 
equilibrium  to  be  established  between  all  the  components  of 
that  system.  All  the  reactions  that  occur  in  a hydrocarbon 
process  are  interrelated  and  must  be  taken  into  considerati on 
even  if  a single  reaction  or  set  of  reactions  may  be  ex- 
tremely important  as  indicating  a prevailing  tendency. 

The  decomposition  of  hydrocarbons  increases  with 
rise  in  temperature  and  with  the  duration  of  time  in  the 
heated  zone.  Le  Chatelier’s  theorem  predicts  that  an 
increase  in  temperature  will  drive  the  reaction  in  the 
direction  in  which  heat  is  absorbed.  Thus  heavy  molecules 
are  less  stable  than  lighter  ones  of  similar  structure. 
Indications  of  the  effect  of  temperature  on  decomposition 
processes  may  be  obtained  from  thermodynamics.  Bertholet 
advanced  a proposition  which  c.:  n be  summarized  as  follows,  - 
every  chemical  change  gives  rise  to  those  substances  that 
occasion  the  greatest  development  of  heat.  If  this  were 
true,  the  problem  of  obtaining  temperature  indications 
would  be  as  simple  as  that  of  obtaining  pressure  indications 
for  reactions  proceeding  to  equilibrium.  That  proposition, 
however,  is  only  a first  approximation,  because  in  all  chem- 
ical reactions  there  is  additional  molecular  energy,  where- 
as the  proposition  mentioned  assumes  the  free  energy, 
termed  maximum  work,  to  be  equal  to  the  total  energy  change. 
Nernst  has  pointed  out  that  this  statement  holds  true  only 
at  the  absolute  zero;  that  is,  the  entropy  of  liquids  and 


■ 


I 


- . • . t,  I 


' 


, 


- - 


* 


' 


• ’ i 

•• 


, 


6 


solids  at  absolute  zero  of  temperature  equals  zero.  The 
temperature  most  favorable  for  the  production  of  the  largest 
quantity  of  any  particular  aromatic  hydrocarbon  is  quite 
different  from  the  optimum  temperature  for  the  formation  of 
a higher  or  lower  homologue.  The  temperature  best  suited 
to  the  formation  of  naphthalene  is  quite  different  from  that 
required  in  the  formation  of  benzene  and  as  we  approach  or 
depart  from  this  optimum  temperature  the  yield  of  the  desired 
hydrocarbon  increase  or  decrease  proportionately. 

When  considering  the  effect  of  pressure  on  a gaseous 
system  similar  difficulties  are  encountered  as  in  the  case 
of  temperature.  The  application  of  Le  Chatelier's  principle 
shows  that  pressure  favors  any  reaction  resulting  in  decrease 
in  volume  and  opposes  any  reaction  that  is  accompanied  by 
an  increase  in  volume.  Stated  in  another  way,  diminished 
pressure,  increases  decomposition  of  hydrocarbons  or  increases 
the  for:jation  of  gas,  while  increase  in  pressure  decreases 
decomposition  or  tends  to  form  liquid  and  solid  compounds. 

It  appears  possible,  therefore,  to  obtain  indications  of  the 
effect  of  pressure  by  simply  writing  the  chemical  equation 
and  summing  up  the  volume  changes.  However,  it  must  be 
remembered  that  pressure  produces  a change  in  the  concentra- 
tion of  the  reacting  substances,  which  may  produce  a marked 
change  in  the  reaction  of  constituents  in  the  system.  Accord- 
ing to  the  law  of  mass  action,  the  velocity  of  a chemical 


7. 


reaction,  at  any  small  intervals  of  time,  is  proportional 
to  the  amount  or  concentration  of  substance  undergoing 
transformation  at  that  time.  So  an  increase  in  pressure 
may  promote  decomposition  or  chemical  change  rather  than 
retard  it,  because  of  the  additional  variables  unavoidably 
introduced  at  the  same  time,  thus  defeating  the  result  de- 
sired . 

The  duration  of  time  of  reaction  is  a very  import- 
ant factor  in  any  gaseous  decomposition.  It  is  intimately 
related  to  the  temperature,  pressure,  gaseous  constituents 
and  end  products  desired.  Organic  reactions  seldom  come  to 
equilibrium  instantly  but  required  a definite  time  inter- 
val. This  time  interval,  in  hydrocarbon  decompositions , can 
be  controlled  in  several  ways,  the  two  easiest  manipulated, 
are  lengthening  or  shortening  the  heated  zone,  or  by 
increasing  or  decreasing  the  rate  of  feed  through  the  heated 
area.  Obviously  a high  temperature  will  require  a lesser 
time  of  contact,  than  a relatively  lower  temperature.  A 
slow  rate  of  feed  and  a relatively  low  temperature  will 
accomplish  practically  the  same  results  as  a relatively 
faster  rate  of  feed  at  a much  higher  temperature,  with 
the  single  difference  that  more  time  will  be  necessary 
for  a given  quantity. 

The  effect  of  contact  surface  is  perhaps  the  most 
indefinite  and  most  important  variable  in  any  hydrocarbon 
decomposition  process.  The  phenomena  of  catalytic  acceler- 
ation or  retardation  of  physical  or  chemical  processes  are 





so  common  as  to  defy  systematic  classification,  since  such 
a complete  system  would  necessarily  include  all  possible 
types  of  reactions,  both  homogeneous  and  heterogeneous. 
Ostwald's  often  quoted  statement,  - "There  is  probably  no 
kind  of  chemical  reaction  which  cannot  be  influenced  cata- 
lytically  and  there  is  no  substance,  element,  or  compound 
which  cannot  act  as  a catalyser",  - indicates  the  comprehen 
sive  susceptibility  of  catalysis. 

Many  theories  have  been  propounded  to  explain  the 
mechanism  of  catalytic  reactions.  Faraday's  concept  of 
catalytic  activity  being  due  to  selective  adsorption 
phenomena  was  advanced  by  J.J.  Thomson1  coupled  with  La- 

o 

place's  theory  of  capillarity.  Bancroft's  latest  state- 
ments, that  selective  adsorption  permits. of  different  reac- 
tions being  accomplished  with  the  aid  of  different  cataly- 
tic materials,  emphasis  two  important  details,  namely, 

4 

catalysts  tend  to  produce  the  system  which  they  adsorb 
most  strongly  and  the  compound  or  adsorptive  layer  may  be 
regarded  as  a solvent  and  hence  may  exert  an  influence  on 
the  final  equilibrium. 

Sabatier*’  , after  many  years  spent  in  investigation 
with  nickel  catalysts  in  hydrogenation  processes,  came  to 
the  conclusion,  that  the  formation  of  an  intermediate  com- 
pound with  the  catalyst  and  reacting  substance,  was  the 
best  explanation  for  this  extraordinary  activity.  In  many 


9 


organic  catalytic  processes,  such  as  the  formation  of  ether, 
Fri edel-Crafts  reaction,  Qrignard  reagent  and  many  others, 
the  intermediate  compound  can  he  isolated.  An  extremely 
interesting  modification  of  this  theory  was  advanced  hy 
Armstrong.  To  him,  chemical  combination  is  reversed 
electrolysis,  and  the  function  of  the  catalyst  is  to  form 
a circuit  containing  a t least  three  distinct  terms  or  com- 
ponents analogous  to  a closed  voltaic  circuit.  By  this  means 
the  catalytic  agent  collects  into  one  system  the  various 
elements  necessary  for  a particular  chemical  change,  and 
may  he  said  to  form  molecular  complexes  with  the  reactants. 

A recent  theory  of  catalysis,  somewhat  of  an  electro- 

5 6 

chemical  nature,  has  been  advanced  hy  Langmuir  and  Harkins. 

i 

According  to  Langmuir,  the  adsorbed  film,  which  is  hound  to 
the  adsorbing  surface  hy  chemical  forces,  namely,  the  primary 
or  secondary  valencies,  should  he  only  one  molecule  thick 
and  in  this  layer  there  exists  an  orientation  of  the  mole- 
cules. He  has  developed  this  general  theory  of  adsorption 
to  the  particular  case  of  the  adsorption  of  gases  hy  plane, 
solid  surfaces,  and  gives  the  results  of  a series  of  ex- 
periments on  the  adsorption  of  various  gases  hy  sheet  plati- 
nuffi,  glass,  and  mica  at  low  pressures  and  various  tempera- 
tures. This  theory  takes  into  account  directive  as  well 
as  selective  adsorption,  thus  bridging  the  gulf  between  the 
theory  of  the  intermediate  compounds  and  the  purely  adsorption 
idea,  since  the  postulate  of  directive  force  necesss.rily 


10 


assumes  some  form  of  chemical  union  between  the  contact  surface 
and  the  molecules  of  the  surrounding  medium.  These  theories  are 
discussed  by  E.  Rideal  and  S.  Taylor  in  their  recent  text, 
"Catalysis  in  theory  and  practice". 

3.  SCOPE  OF  PREVIOUS  INVESTIGATIONS. 

In  the  following  resume  on  pyrogenetic  reactions 
of  aromatic  hydrocarbons  only  those  investigations  that 
seem  most  important  in  connection  with  the  present  problem 
are  mentioned.  Much  work  has  been  done  on  the  problem 
of  thermal  reactions  of  aromatic  hydrocarbons,  but,  on  ac- 
count of  the  many  variables  encountered,  no  systematic 

study  of  these  reactions  have  appeared  in  the  literature. 

7 

The  historical  researches  of  Bertholet  have 
furnished  a foundation  for  succeeding  investigations  with 
pure  aromatic  hydrocarbons.  His  work  was  comprehensive  and 
the  results  obtained  very  valuable.  He  passed  the  vapors 
of  pure  hydrocarbons  through  "red  hot  tubes"  and  obtained 
the  general  results  as  follows:  from  benzene  he  obtained 

diphenyl,  chrysene  and  resin;  from  toluene  he  recovered 
benzene,  toluene,  naphthalene,  anthracene  and  chrysene; 
from  xylene  he  collected  benzene,  toluen^  xylene,  nap- 
hthalene, and  anthracene;  while  anthracene  yielded  benzene 
and  chrysene.  Prom  the  mixed  vapors  of  naphthalene  and 
benzene  he  obtained  anthracene  and  from  benzene  and  ethy- 
lene he  recovered  anthracene  and  diphenyl . Ho  yields  of 
products  are  reported  in  these  publications  and  the  temper- 
ature designated  by  the  term  "red-hot"  is  very  indefinite. 


. 


. 


• ■ 


. 

' 

■ 

, 

' 

■ 


- . 


. 


. 


■ 


. 


Recently,  ZanetiA  and  Kendall  have  studied  the 
pyrogenetic  production  of  anthracene  from  henzene  and 
ethylene  in  a quantitative  manner  and  at  various  tempera- 
tures. They  bubbled  the  ethylene  through  the  benzene  and 
passed  the  vapors  through  a hhated  quartz  tube.  Their  best 

yield,  (0.675$  from  the  total  benzene  used),  was  obtained 
o 

at  925  C and  at  atmospheric  pressure.  At  this  temperature 
the  sum  of  the  yields  of  diphenyl  and  carbon  is  a minimum 
and  above  it  the  formation  of  carbon  occurs  very  rapidly. 

In  some  previous  experiments  conducted  by  Za.netti 

9 

and  Egloff,  on  the  thermal  decomposition  of  benzene  with 
catalysers,  they  found  that  benzene  could  be  decomposed 
to  diphenyl  at  a temperature  as  low  as  500°  C.  but  did  not 
believe  that  copper  iron  or  nickel  gauze  inserted  in  the 
craking  tube,  catalysed  the  reaction.  However,  iron  and 
nickel  did  seem  to  catalyse  the  reaction  to  carbon  and  hy- 
drogen . 

Some  valuable  information  indicating  the  direction 
of  reactions  in  the  thermal  decomposition  of  hydrocarbon 
vapors  was  obtained  by  Eerko^  by  passing  the  vapors  through 
a "red  hot”  iron  tube.  The  temperature  he  used  was  very 
indefinited  and  the  pressure  is  not  mentioned,  no  doubt,  the 
results  given  are  at  atmospheric  pressure.  From  benzene 
and  ethylene  he  recovered  benzene,  stryolene,  diphenyl, 
phenanthrene  and  anthracene;  from  toluene  he  obtained  ben- 
zene and  anthracene;  while  from  toluene  and  ethylene  he  iden 


12 


tified  benzene,  toluene,  stroylene  and  anthracene.  These 
results  show  that  no  reaction  products  were  obtained  that 
were  not  in  the  order  of  decrease  of  saturation  or  of  mole- 
cular weight  if  the  saturation  remained  unchanged.  That  is, 
benzene  yielded  no  toluene  nor  any  other  compound  of  equal 
saturation  and  of  greater  molecular  weight.  Naphthalene  gave 
neither  benzene  or  toluene  but  small  amounts  of  dinaphtha- 
lene and  phenanthene. 

Prom  Haber’s11  work  on  the  thermal  decomposition  of 
hydrocarbons  he  found  that  benzene  decomposes  with  difficulty 
above  900°C  and  although  it  goes  readily  to  diphenyl  and 
hydrogen  no  naphthalene  is  formed.  He  concludes  that  in 
aromatic  hydrocarbons  decomposition  takes  place  between 
carbon  and  hydrogen  atoms. 

1 p 

In  some  qualitative  experiments  by  McKee  in  which 

he  passed  benzene  vapors  through  a copper  tube  at  tempera - 

o o 

tpres  ranging  from  450  C to  785  C,  he  concluded  that  the 

order  of  hydrocarbon  decomposition  is  as  follows*  higher 

paraffines  — » lower  paraffins  — ^ Olefins  — » 

acetylenes  — * benzene  and  homologues  — » diphenyl  — * 

naphthalene , etc . — » tarry  matter  — » carbon  and  gas. 

No  analysis  or  separation  of  the  products  was  attempted,  he 

merely  determined  the  degree  of  decomposition  by  the  change  in 

the  specific  gravity  of  the  product. 

13 

Ipatieff  found  that  benzene  decomposed  with  the 

liberation  of  hydrogen,  forming  diphenyl  above  600°C. 

14 

Ostromisslenske  and  Burshanadse  found  that  when  benzene 
vapor  was  passed  over  nickel  or  nickel  oxide  at  temperatures 
of  600°  to  750°  C,  carbon  and  hydrogen  were  the  main  products. 


1 5 

Siiiith  and  Lewcock  passed  benzene  vapors  through  an 
iron  tube  containing  different  catalysers  such  as  barium  oxide 
and  coke,  and  found  that  diphenyl  was  not  formed  below 
670°C.  but  at  800°C.  they  obtained  a 25%  yield  of  diphenyl. 

They  could  not  reverse  the  reaction,  and  noticed  that  the 
yield  of  diphenyl  increased  with  the  rate  of  feed , indicating 
that  diphenyl  was  an  intermediate,  rather  than  an  equilibrium 
product . 

i (i 

Rittrnan,Button  and  Dean-1*  in  their  pyrogenetic 
decomposition  of  aromatic  hydrocarbons,  in  the  vapor  phase, 
passed  benzene,  toluene,  xylene,  naphthalene  and  anthracene 
through  iron  tubes  at  temperatures  ranging  from  650°  to 
800°C  and  from  diminished  pressure  up  to  pressures  of  18 
atmospheres.  They  also  came  to  the  conclusion  that  the 
course  of  the  reaction  is  in  the  direction  of  the  decrease 
in  the  size  of  the  molecule,  when  the  degree  of  saturation 
remains  unchanged.  Dehydrogenation,  either  with  an  increase 
or  decrease  in  the  size  of  the  molecule,  may  occur  but 

the  reverse  reactions  are  negligible. 

17 

Charlton  made  three  distillations  olf  xylene 
at  temperatures  between  600°C  and  700°C  through  an  iron  tube 
containing  charcoal,  also  with  charcoal  impregnated  with 
nickel,  in  the  presence  of  superheated  steam,  to  determine 
the  relative  yields  of  toluene  and  benzene.  At  650°q  q n ^ 

atmospheric  pressure,  when  using  nickel  charcoal  catalyser, 


14. 


the  recovered  "benzene  equalled  0.33$,  and  the  toluene 
0.40$,  while  the  higher  boiling  fraction  equalled  4.56$  of 
the  toluene  used.  Another  experiment  at  the  same  temperature 
using  the  same  catalyser  but  allowing  the  superheated  steam 
to  build  the  pressure  up  to  40  pounds  per  square  inch,  pro- 
duced 0.958$  benzene,  3.6$  toluene  and  9.12$  higher  boil- 
ing compounds.  When  running  under  110  pounds  pressure  the 
yield  of  benzene  increased  to  1.45$  but  the  other  products 
became  less. 

It  is  interesting  to  note  that  at  atmospheric  and 
40  pounds  pressure  no  paraffine  hydrocarbons  were  obtained 
but  as  high  as  28.0$  unsaturated  aliphatics  were  found  in 
the  product.  At  110  pounds  pressure  the  unsaturated  com- 
pounds were  reduced  100$  while  10.0$  of  paraffines  were 
obtained.  In  the  high  boiling  oils,  monomethyl  anthracene 
separated  out  but  no  naphthalene  was  found  in  any  of  these 
experiments . 

1 8 

In  the  researches  of  Cobb  and  Dufton,  on  the 
thermal  decomposition  of  pure  aromatic  substances,  benzene, 
toluene,  xylene,  and  cresol,  were  vaporized  and  passed 
through  a silica  tube  containing  coke  at  various  tempera- 
tures, in  the  presence  of  hydrogen  or  nitrogen  and  the  de- 
composition products  collected  and  analysed.  These  results 
are  the  most  important  of  any  published  along  this  line. 

They  found  that  benzene  could  be  stabalized  at  temperatures 
of  750°C  by  having  the  gaseous  mixture  consist  of  93  per 


. 


( 


15 


cent  hydrogen.  Under  low  concentrati ons  of  hydrogen 
diphenyl  was  formed.  They  proved  that  the  diphenyl  formation 
was  an  equilibrium  reaction  by  saturating  hydrogen  with 
diphenyl  vapors  at  90°C  and  passing  the  mixture  through 
the  tube  at  750°  and  obtaining  benzene.  From  toluene 
they  recovered  benzene,  ditolyl  and  anthracene  and  from 
xylene  they  obtained  benzene,  toluene,  diphenyl,  and  anthra- 
cene. These  results  are  given  on  a quantitative  basis  to- 
gether with  much  other  valuable  information. 

4.  OUTLINE  OF  THE  PRESENT  INVESTIGATION. 

The  object  of  the  present  experimental  work, 

broadly  stated,  was  to  determined  the  effect  of  various 

combinations  of  temperature,  pressure,  concentrati on , 

and  contact  surfaces  on  the  course  of  decomposition  reactions 

of  aromatic  hydrocarbons,  in  the  vapor  stage,  and  to  determine, 

if  possible,  the  most  favorable  conditions  for  the  maximum 

yield  of  the  various  desired  decomposition  products,  such  as 

benzene,  toluene  or  anthracene.  In  the  extensive  experimental 

work  carried  on  in  these  laboratores  on  the  coking  of  Illi- 
19 

nois  coals.’*'  Utah  coals,  and  xaany  other  varieties,  it  has 
been  found  possible  to  increase  the  quantity  of  tars  and 
oils  produced  from  two  to  four  fold,  by  means  of  low 
temperature  carbonization.  The  distillate  obtained,  in  this 
manner,  contains  a large  quantity  of  neutral,  low  boiling 


16. 


1 


aromatic  oils,  some  of  which,  under  noruial  commercial  con- 
ditions, are  considered  of  little  irn.ports.nce  in  the  industrial 
field.  For  instance,  xylene  in  its  present  status,  is  a 
product  scarcely  worthy  of  recovering  and  purifying,  yet  by 
application  of  known  methods  of  recovery,  could  be  produced, 
under  present  conditions,  in  enormous  quantities.  This  hy- 
drocarbon, having  a boiling  point  of  137  to  141  C has  too  low 
a vapor  pressure  for  an  efficient  motor  fuel,  however,  if  by 
methods  of  pyrogenic  decomposition,  it  can  be  converted  into 
benzene,  which  has  a boiling  point  of  80°C,  its  value  as  a 
motor  fuel  is  greatly  increased.  If  this  decomposition  can  be 
accomplished,  in  yields,  approaching  anything  like  theoretical 
and  in  commercial  quantities,  the  hydrogen  and  methane  li oerst- 
ed ought  to  more  than  supply  the  heat  energy  required  in  the 
operation.  Xylene  can  be  decomposed  with  anthracene  as  an 
end  product,  but  under  existing  methods  the  yield  is  small. 

If  this  dec omposit ion  could  be  made  on  a commercial  scale  and 
in  yields  sufficient  to  warrant  its  use,  one  of  the  main  props 
in  the  synthetic  dye  industry  would  be  assured.  3ver 
since  1856  when  Perkin  produced  the  first  alizarin  dye 
from  anthracene , the  increase  in  production  of  this  hydrocar- 
bon has  been  eagerly  sought.  During  the  last  few  years  it  has 
been  demonstrated  how  important  the  dye  industry  in  this 
country  has  become. 

In  this  investigation  pure  xylene  was  passed  through 
an  electrically  heated  furnace,  at  various  temperatures, 


17 


different  rates  of  feed,  under  various  pressures,  in  the 
presence  of  such  contact  surfaces  as  iron  oxides,  reduced  iron, 
copper,  tin,  molybdenum,  chromium,  Illuiin,  aluminium,  nickel, 
cobalt,  manganese,  charcoal,  pumice  and  refractory,  the 
condensable  compounds  collected,  weighed  and  analysed,  also  the 
gas  was  measured  and  analysed.  Hot  only  was  the  above  variables 
tried  out  but  the  vapor  condition  inside  the  furnace  was  in- 
fluenced by  passing  in  at  the  same  time  as  the  hydrocarbon , air , 
superheated  steam,  carbon  dioxide,  carbon  monoxide,  hydrogen, 
nitrogen  or  ethylene. 

5.  GROUPING  OP  RESULTS  OP  THE  INVESTIGATION. 

The  facts  established  by  this  investigation  rnay  be  brieflj'- 
summarised  as  follows: 

(1)  Mixed  xylenes  were  decomposed  by  heat  and  contact  sur- 
faces, under  the  stabilizing  influence  of  hydrogen  and  methane, 
almost  theoretically  into  benzene  and  methane.  Sixty-nine 
percent  of  the  original  xylene  was  convered  into  crude  benzene, 
which  boiled  below  100°C . This  is  approximately  94.0  percent 

of  the  possible  theoretical. 

(2)  At  slightly  lower  t emperatures , under  the  same  con- 
ditions of  contact  surfaces,  but  in  a gaseous  atmosphere  in 
which  ethylene  greatly  predominated, seventy-seven  percent  of 
the  mixed  xylenes  were  built  up  into  higher  boiling  com- 
pounds, the  majority  of  which  were  solids  at  ordinary  temper- 
atures . 

(3)  Mixed  xylenes,  under  other  conditions  of  temperature 
and  contact  surfaces,  were  converted  into  crude  toluene,  in 


18 


quantities  approximating  64.0  percent  of  the  possible  theoreti- 
cal . 

(4)  Mixed  xylenes,  under  the  influence  of  heat  and  iron 
surfaces,  were  decomposed  quantitatively  into  amorphous  carbon 
and  gaseous  products.  Small  particles  of  iron  oxides  and  reduced 
iron  were  found  in  the  deposited  carbon. 

(5)  Activation  of  heated  iron  and  carbon  surfaces  could 
be  induced  by  treating  with  superheated  steam  during  a short 
period,  and  afterwards  slightly  reducing  with  hydrogen. 

(6)  A deadening  effect,  opposite  in  characteristics 

to  the  above,  was  caused,  when  carbon  dioxide,  carbon  monoxide, 
air  or  superheated  steam  was  passed  through  the  activated 
fulrnace.  This  condition  seemed  to  be  the  same  as  is  ordinarily 
described,  as  poisoning  of  the  catalyser. 

(7)  The  decomposition  of  ethylene  was  controlled  so  that 
practically  pure  methane,  or  mixtures  of  methane  and  ethane 
were  obtained  as  end  products. 

(8)  The  following  gaseous  products  were  synthesised  from 
mixed  xylene:  Ethylene,  methane , ethane , acetylene  and  carbon 
oxides. 

(9)  among  the  liquid  products  synthesised  from  mixed 
xylene:-  n-hexane,  cyclohexane,  benzene,  toluene,  ditolyls, 
methylnaphthalene,  and  diphenyl ethane  have  been  identified. 

(10)  The  solids  synthesised  from  mixed  xylenes  contained 
diphenyl,  naphthalene,  stilbene,  methyl  anthracene,  p-diphenyl 
benzene,  anthracene  and  methy  derivitives. 


18A 


19 


II. 

EXPERIMENTAL  WORK. 


1.  APPARATUS. 

The  essential  parts  of  the  apparatus  are  shown  in  the 
accompanying  photographs  and  drawing.  The  complete  outfit, 
being  of  a conventional  type,  requires  little  explanation  with 
the  possible  exception  of  the  furnace.  It  was  made  by  taking 
six  feet  of  four  inch,  Ho.  18  Byer's  pipe,  threading  on  flanges 
and  thermo  couple  pockets  and  then  having  these  joints  acety- 
lene welded  to  insure  having  no  leaks  under  conditions  of  high 
temperature  and  pressure.  The  caps  were  cast  particularly  for 
this  furnace  and  extended  l-g-  inches  into  the  end  of  the  pipe 
and  were  fitted  with  three, three-quart er-inch  threaded  open- 
ings leading  into  the  furnace.  The  pipe  was  thinly  coated  with 
alundum  cement;  wound  in  five  sections,  each  having  36.5  feet 
Ho.  1.4A  chrorael  resistance  wire  and  again  coated  with  cement. 

It  was  surrounded  by  a wooden  box  twenty  inches  square  and  as 
long  as  the  furnace,  which  contained  the  pulverized  asbestos 
and  Sil-O-Cel  insulation.  Each,  heating  element,  when  connected 
directly  across  the  110  volt  line,  allowed  a maximum  current 
of  20  amperes  to  pass  through  but  this  could  be  reduced  to 
5 amperes  by  means  of  an  external  resistance  connected  in 
series  at  the  switch  board.  At  no  time  was  more  than  10  amperes 
allowed  to  go  through  the  heating  elements.  By  this  means  the 
heat  of  the  furnace  could  be  kept  constant  at  any  desired 


20. 


temperature  between  250  and  900  C.  The  top  end  was  fitted 
with  feed  pipes  for  xylene,  superheated  steam  and  other  gases, 
also  with  a pressure  and  reduced  pressure  gauge.  On  the  exit 
at  the  bottom  end  was  a safety  relief  valve,  or  constant 
pressure  valve,  which  could  be  adjusted  to  let  the  gases  ex- 
cape into  the  line,  leading  to  the  gas  meter,  at  any  desired 
pressure.  This  outfit  has  been  operated  under  180  pounds  pres- 
sure per  square  inch.  The  temperature  was  measured  by  means 
of  a thermocouple  made  from  six  feet  of  No.  8 Chromel  s-nd 
alurnel  wire.  The  cold  junction  was  kept  at  zero  by  means  of  a 
thermos  bottle  well  and  ice  water,  the  e.m.f.  was  read  on  a 
millivoltmet er  which  had  been  standardized  at  knownt empera- 
tures.  By  this  method  the  temperature  could  be  read  accurate- 
ly within  four  or  five  degrees.  The  thermocouple  pockets  (k) 
extended  into  the  middle  of  the  furnace  and  thus  gave  the 
temperature  of  the  area  where  the  largest  volume  of  vapors 
passed . 


EGA 


Pig.  1.  Upper  end  of  Furnace 


2 OB 


Fig.  2.  Lower  end  of  furnace 


21. 


2.  METHOD  OE  OPERATION. 

The  mechanical  arrangement  of  the  apparatus  is  appar- 
ent from  the  explanation  of  the  progressive  steps  of  a typi- 
cal run.  The  xylene  was  placed  in  the  reservoir  (A)  fed  hy 
means  of  a regulating  valve  through  the  sight-glass,  or  by- 
pass (B)  into  the  upper  end  of  the  furnace  (C).  Here  also, 
could  he  introduced  gas,  such  as  hydrogen,  nitrogen,  carbon 
dioxide  or  ethylene  from  the  cylinder  (I),  or  from  the  high 
pressure  steam  line  (J)  through  the  gas-fired  superheater  (H) 
could  be  introduced  steam.  Another  attachment,  not  shown  in 
the  picture,  permitted  the  use  of  compressed  air.  In  passing 
down  through  (C)  the  vapors  came  into  contact  with  the  various 
contact  surfaces  used.  The  highest  boiling  condensate  was 
collected  in  receiver  (i)  the  medium  oils  in  No.  (2) 
while  the  gases,  after  passing  through  the  water  cooled  con- 
densers (D)  were  scrubbed  with  heavy  oil  in  receiver  (3).  The 
gas  leaving  receiver  (3)  passed  through  pipe  (E)  to  be  meas- 
ured by  the  meter  ( E)  and  was  then  burned,  or  analysdei  by 
means  of  the  modified  Orsat  apparatus  (G).  When  run- 
ning under  increased  pressure,  extra  lengths  of  piping, fitt ed 
with  a gate  valve,  were  attached  to  the  ends  of  the  condensers 
By  keeping  the  lower  valve  closed  and  the  upper  one  open,  tne 
condensate  collected  between  them  and  could  be. 

easily  removed,  by  closing  the  upper  valve  and  opening  the 
lower  one,  without  causing  any  change  in  the  pressure  within 


the  furnace. 


. 

, ■ 

• : 

• 

* 

• 

4 

22. 


3.  METHOD  OF  ANALYSING  PRODUCTS. 

The  condensable  products  were  weighed,  fractionated 

through  a six-inch  wash  column  of  glass-beads,  until  all  the 

o 

liquid  boiling  below  145  C was  removed.  The  liquid  boiling 

above  145°C,  designated  in  the  following  experimental  results 

as  high  boiling  product,  was  then  transferred  to  an  ordinary 

pyrex  distilling  flask  and  the  fractionation  continued  until 

all  but  coke  was  driven  over.  These  operations  were  performed 

by  means  of  electrically  heated  furnaces  similar  to  those 

17 

fully  described  by  Charlton. 

The  solids  obtained  from  the  high  boiling  oils  were 
purified  and  analysed  by  a combination  of  various  methods, 

1 7 pi  op 

as  described  by  Charlton,  , Clark  , Cook^~  and  others.  These 
will  be  fully  explained  in  a succeeding  thesis  now  being 
prepared  in  these  laboratories  by  Mr.  Malecki. 

The  non-condensable  or  gaseous  products  were  analysed 
by  means  of  a modified  Orsat  apparatus  which  has  been  con- 
structed in  these  laboratories.  A full  description  of  this 
apparatus  will  be  submitted  for  publication  to  one  of  the 
technical  journals.  The  carbon  dioxide  was  removed  by  35% 
potassium  hydroxide;  oxygen  by  potassium  pyrogAllate;  acetylene 
by  ammonical  silver  chloride;  ethylene  by  bromine  water; 
aromatics  by  20%  fuming  sulfuric  acid;  hydrogen  and  carbon 
monoxide  by  combustion  at  28©-300°C  with  copper  and  ceric 
oxides;  ethane  and  methane  by  slow  combustion  in  pure  oxygen; 
while  the  nitrogen  was  estimated  by  difference.  It  is  realized 


23. 

that  an  exact  separation  of  acetylene  and  ethylene  cannot  he 
obtained  in  theabove  manner  but  by  leaving  the  gaseous  mix- 
ture in  contact  with  the  ammonical  silver  chloride  solution 
during  a constant  time  interval  in  each  analysis,  a relative 
idea  of  these  two  constituents  can  be  obtained. A Complete 
analysis  could  be  made  in  less  than  thirty  minutes,  except  in 
cases  where  the  carbon-monoxide  content  was  high.  Carbon  mono- 
xide seemed  to  poison  the  copper  and  ceric  oxides  and  thus 
greatly  retard  this  combustion. 

4.  SPECIFICATION  OF  THE  HYDROCARBONS  USED  IN  THE  INVESTIGATION. 

The  mixed  xylene,  the  commercial  product  put  on 
the  market  by  the  Barrett  Co.  in  10  gallon  tin  cans,  was 
used  in  the  major  portion  of  this  work.  It  was  water- 
white,  contained  no  suspended  material,  was  free  from 
moisture,  had  no  foreign  odor,  practically  all  distilled 
between  13?  and  142°C,  and  had  a specific  gravity  of  0.8664, 
at  15.5°C . 

The  benzene,  toluene  and  naphthalene  used  were 
the  commercial  products  in  stock  at  the  chemistry  store- 
room. They  were  not  analysed  or  purified  in  any  way. 

In  fact,  only  a few  runs  were  made  with  them,  to  try 

to  check  up  on  the  results  obtained  from  xylene,  under  similar 

conditions  in  the  furnace. 

5.  RESULTS  OF  PRELIMINARY  RUNS. 

By  the  term  ’’run"  is  meant  the  operation  of  feeding 


24. 


a definite  quantity  of  material  into  the  furnace,  at 
any  desired  temperature,  during  a constant  time  interval. 

Or  stated  in  another  way,  feeding  the  material  at  a constant 
rate;  this  rate  was  changed  to  suit  the  other  conditions  hut 
was  constant  during  any  series  of  runs.  After  all  the  material 
had  been  passed  into  the  furnace  about  thirty  minutes  were  re- 
quired for  the  final  traces  of  the  condensate  to  drain  out 
and  the  evolution  of  gas  to  be  completed. 

In  order  to  try  out  the  effect  of  temperature 
and  the  iron  furnace  surface  on  the  xylene  a series  of 
runs  were  made  at  atmospheric  pressure,  with  1000  grams 
of  xylene,  at  each  50°C  rise  in  temperature,  between  200  and 
600°C.  Each  run  required  one  hour.  In  this  series  of  nine 
runs,  the  loss  was  less  than  one  percent,  the  gas  given  off 
was  too  small  to  warrant  analysing,  while  the  condensate 
proved  to  be  almost  entirely  unchanged  xylene.  Naturally  it 
was  concluded,  that  the  effect  of  the  iron  surface  at  various 
temperatures,  was  practically  negligible  and  could,  very  con- 
viently,  be  neglected  for  all  practical  purposes  in  this  in- 
vestigation. However,  before  the  work  had  proceeded  very  far, 
this  was  found  to  be  an  erroneous  conclusion.  The  iron  sur- 
face could  be  " activated"  or  " deadened”  in  such  a way  as 
to  produce  diversified  results. 


6.  SERIES  OF  RUN’S  USING  CHARCOAL  SURFACES. 


25. 


This  series  of  runs  were  to  ascertain  the  effects 
of  iron  and  charcoal  surfaces  under  similar  conditions 
as  recorded  previously.  A piece  of  sheet  iron,  3/16 
inches  thick  and  five  feet  long,  which  had  been  drilled 
with  5/8"  holes  3/8"  apart,  was  made  into  a tube,  which  fitted 
snugly  into  the  furnace.  In  this  perforated  tube  was  placed 
approximately  two  kilos  of  wood  charcoal,  which  had  been  cut 
into  cubes  between  l/2  and  3/4  inch  square. 

In  these  runs  1000  gms.  of  xylene  was  used  as 
before.  The  first  run  was  made  at  250°C  and  in  it  the  loss 
of  xylene  amounted  to  4 percent.  This  was  no  doubt  due 
to  absorxjtion  by  the  charcoal.  *.3  the  temperature  was 
raised,  more  moisture  was  driven  from  the  charcoal  and 
the  percentage  of  carbon  monoxide  in  the  gas  increased. 

Below  450°C  very  little  change  was  noted  in  the  recovered 
xylene,  or  in  the  volume  of  gas  given  off.  In  fact,  the 
total  loss  of  xylene  was  only  about  one  to  two  percent. 

The  results  of  the  runs  above  450°C  are  shown  in  Table  No. 

I.  In  this  table,  as  in  all  the  following,  the  analysis  of 
the  escaping  gas  is  given  first;  then  the  total  amount  of 
gas  given  off  in  the  reaction,  expressed  in  cubic  feet;  then 
co. nes  the  loss,  in  weight  percent  of  the  original  xylene 
used  in  the  run  and  finally  a partial  distillation  analysis 
of  the  recovered  condensate  on  the  same  basis.  These  cuts 


26. 


are  made  at  arbitrary  temperatures  best  suited  to  the 
distilling  flask  and  wash-column  used.  In  closer  analytical 
work,  it  was  found  that  the  maximum  portion  of  the  fraction 
passing  over  up  to  105°C  consisted  of  benzene,  between  105  and 
130°C  to  be  toluene  and  between  130  and  145°C  to  be  xylenes. 

Of  the  product  boiling  above  145°C,  375  grams  was 
distilled  from  an  ordinary  pyrex  distilling  flask  and  per- 
centage boiling  between  different  temperatures  is  shown  in 
the  summary. 


TABLE  I 

Summary  of  runs  through  furnace,  containing  2£  kilos 
of  charcoal  cubes.  In  each  run  1000  gm3 . of  xylene  was  used 


and  required  twc 

• hours  to 

feed 

into 

the  ; 

furnace. 

No . of  Run 

20 

21 

22 

23 

24 

25 

26 

27 

Pressure  lbs. 

All 

At  mo 

spheric 

Temperature  C 

450 

500 

550 

600 

650 

700 

750 

800 

Carbon  Dioxide 

6.  9 

10.2 

6.4 

1.6 

0.2 

0.2 

0.0 

0.1 

Oxygen 

7.2 

2.8 

1.7 

1.3 

0.5 

0.4 

0.4 

0.1 

Acetyl ene 

0.0 

0.4 

0.2 

1.2 

1.0 

0.4 

0.3 

0.2 

Ethylene 

0.1 

0.2 

0.3 

3.4 

4.3 

2.2 

1.7 

1.4 

Aromatics 

0.0 

0.1 

3.1 

12.2 

8.0 

3.1 

2.7 

1.6 

Hydrogen 

2.6 

10.8 

19,2 

37.0 

61.1 

50.6 

45.0 

45.6 

Carbon  Monoxide 

2.2 

7.4 

0 . 6 

1.7 

1.8 

0.2 

0.7 

0.9 

Ethane 

2.2 

1.0 

4.8 

7.1 

3.2 

2.3 

0.8 

0.0 

Methane 

0.7 

.9 

12.6 

23.9 

19.2 

25.7 

39.4 

48.3 

Nitrogen 

80.4 

66.2 

50.9 

10.8 

0.7 

14.8 

9.0 

1.8 

Total  ga3  cu.ft. 

0.2 

0.2 

0.2 

1.0 

2.3 

6.9 

8.4 

8.0 

Percentage  Loss 

6.0 

2.0 

5.0 

7.0 

22.5 

23.5 

34.0 

50.0 

Up  to  105°C 

• • • 

• • • 

• • • 

• • • 

#tr 

#tr 

13.0 

5.0 

105  to  130°C 

• • • 

• • • 

• • • 

• • • 

15.5 

16.0 

8.7 

130  to  145°C 

94.0 

98.0 

95.0 

93.0 

73.5 

54.0 

19.4 

24.1 

Above  145°C 

• • • 

• • • 

• • • 

#tr 

4.0 

7.0 

16.2 

12.2 

145  to  175°C 

11.2 

175  to  225°C 

3.8 

225  to  300° C 

24.6 

300  to  Coke 

41.4 

Coke 

13.9 

28. 


o 

In  the  heavy  oils  "boiling  "between  225  and  300  0 a white 
solid  separated  out  on  standing;  while  "between  300  and  400°C  a 
yellowish  solid  was  deposited;  while  above  400  C the  product  was 
a yellowish  solid  at  ordinary  temperatures.  The  fraction  coming  over 
around  450°C  was  a reddish  tarry  substance  and  the  last  traces 
driven  off  were  dense  red  fumes. 

In  all  the  above  runs  more  or  less  water  was  found  in 
the  condensate.  This  may  have  been  held  mechanically  by  the 
charcoal,  or  the  result  of  reduction  of  some  oxides,  probably 
iron  oxides. 

The  table  shows  very  plainly  the  stability  of  xylene 

under  these  conditions,  decomposition,  in  appreciable  amounts 

o o 

commencing  around  650  C while  at  750  0 the  yields  of  the  desired 
products  is  maximum.  It  is  also  interesting  to  note  the  change 
in  percentage  of  ethane  and  methane  with  temperature.  Methane 
being  much  ,uore  stablfe  at  higher  temperatures.  As  would  be  ex- 
pected, the  total  loss  and  amount  of  gas  produced  increases  with 
rise  in  temperature.  The  nitrogen  content  of  the  first  analyses 
is  high,  owing  to  the  fact  that  the  gas  coming  off  was  not  suf- 
ficient to  sweep  the  entire  outfit  free  from  air.  All  gas  samples 

#Note.  In  all  gas  analysis  nitrogen  is  estimated  by  substract- 
ing  the  sum  of  all  the  constituents  from  100.  The  abbreviation 
Tr.  indicates  a very  small  amount  less  than  one  percent.  All 
distillation  cut3  are  given  in  weight  percent  of  the  original 
xylene  used. 


* ' 


' 


■ 


* 


. 


■ 1 i 


* 


, 


29.  j 

were  taken  when  the  run  was  about  three  quarters  completed.  It 
was  supposed  that  the  conditions  within  the  furnace,  at  that 
time  would  he  as  near  representative  as  possible  for  the  run.  The 
gas  was  always  analysed  directly  before  passing  through  the  meter. 
That  is,  the  constituent  ratio  was  not  changed  by  allowing  the  gas 
to  be  stored,  during  varying  periods,  over  liquid,  before  analy- 
sing. 

When  the  series  of  runs  were  completed,  the  furnace  was 
allowed  to  become  cold  and  the  cap  removed  from  the  exit  end.  The 
charcoal  in  the  lower  half  of  the  furnace  was  entirely  consumed, 
leaving  a gray,  fluffy  ash;  the  top  half  did  not  seem  to  have 
been  changed,  except  being  somewhat  more  lustrous  in  appearance. 
Between  the  perforated  tube  and  the  walls  of  the  furnace  was  a 
compact  deposit  of  carbon,  which  made  it  somewhat  difficult  to  re- 
move the  inner  tube.  As  the  furnace  had  been  kept  at  a constant 
temperature  for  a considerable  time  before  each  run,  it  was 
concluded  that  this  deposit  was  not  due  entirely  to  higher 
temperature  right  at  the  walls  of  furnace  but  that  the  iron 
surface  was  in  some  way  or  other  promoting  decomposition  of  the 
xylene . 

The  next  series  of  runs  were  made  over  2-g-  kilos  of  char- 
coal cubes.  These  were  cut  in  sizes  varying  from  3/4  inches  to 
l/4  inch  square.  The  larger  size,  being  placed  in  the  furnace 
near  the  inlet  and  the  smallest  at  the  exit  end.  By  this  means 
more  surface  was  exposed  to  the  outgoing  vapors.  The  furnace  was 


— — — — — - — — — — - — 3ur~ 

then  closed  and  live  steam  at  125  pounds  pressure  was  turned  on  to 
make  sure  that  there  were  no  leaks  in  the  outfit.  It  was  found  out 
later  that  steaming  the  charcoal  greatly  modified  its  activity 
in  decomposition  processes. 


> 


3T 


TABLE  II. 

Summary  of  runs  over  2 £ kilos  of  charcoal  cubes,  which 
had  been  subject  to  live  steam  at  125  pounds  pressure,  before  the 
furnace  had  been  heated  up.  1000  gms.  of  xylene  used  per  run 
requiring  two  hours. 


No.  of  Runs 

30 

31 

32 

33 

34 

35 

36 

Pressure  lbs. 

Atm 

Atm 

Atm 

Atm 

Atm 

Atm 

Atm 

Temperature  C, 

550 

600 

700 

665 

625 

600 

550 

Carbon  Dioxide 

0.9 

1.4 

0.9 

0.0 

0.1 

0.0 

0.0 

Oxygen 

4.4 

6.0 

0.2 

0.3 

0.1 

0.0 

0.4 

Acetylene 

1.6 

0.8 

0.8 

0.7 

0.9 

0.5 

0.3 

Ethylene 

1.8 

3.0 

0.2 

0.1 

0.0 

0.0 

0.2 

Aromatics 

0.7 

12.6 

1.0 

1.4 

1.0 

1.0 

1.0 

Hydrogen 

28.4 

29.0 

75.2 

71.9 

75.8 

72.9 

79.6 

Carbon  lion  oxide 

0.3 

0.8 

5.7 

3.0 

0.4 

0.2 

0.1 

Ethane 

20.5 

0.0 

6.7 

1.2 

1.8 

0.0 

0.0 

Methane 

12.6 

32.0 

6 . 6 

21.5 

18.4 

24.1 

17.5 

Nitrogen 

28.8 

14.4 

2.7 

0.0 

1.5 

1.3 

0.9 

Total  gas  cu.ft. 

0.3 

0 .7 

4.0 

25.6 

25.4 

25.2 

18.0 

Percentage  loss 

4.0 

38.7 

100.0 

100.0 

100.0 

84.5 

Up  to  105°C 

tr 

tr 

6.5 

• • • 

• • « 

• • • 

10.0 

105  to  130°C 

25.3 

15.0 

1.0 

• • • 

• • • 

• • • 

3.0 

130-145°C 

72.5 

77.7 

49.8 

• • • 

• • • 

• « • 

0.0 

Above  145°C 

1.8 

3.3 

4.0 

• • • 

• • • 

• • • 

2.7 

In  run  30  it  is  interesting  to  note  the  amount  of  ethane 
formed .Also , these  conditions  seemed  most  favorable  for  the 


' 


52 


production  of  the  toluene  fraction.  As  the  temperature  rose,  the 
toluene  fraction  became  less,  while  the  hydrogen  content  of  gas 
greatly  increased.  Near  the  end  of  run  52,  the  temperature 
fell  rapidly  to  655°C  due  to  a different  reaction  taking  place 
in  the  furnace.  At  the  same  time,  a marked  increase  was  noted 
in  the  gas  produced  while  the  condensate  decreased.  Runs  55,54, 

55  and  56  were  made  on  decreasing  temperature  conditions.  As  the 
table  indicates,  the  destruction  of  xylene  was  complete,  hydrogen, 
methane  and  carbon  being  the  final  products.  As  the  temperature 
was  lowered,  to  ascertain  at  how  low  a temperature  this  reaction 
would  continue,  some  traces  of  condensate  was  obtained  at  550°C. 

As  the  temperature  decreased  from  this  point  the  condensate  in- 
creased. 

The  current  was  shut  off  and  the  furnace  openings  closed, 
so  that  no  air  could  enter  the  outfit.  After  standing  for  four  days 
the  furnace  was  again  heated  up,  without  any  change  having  been 
made  in  any  particular  from  the  previous  conditions,  and  a 
series  of  runs  made  as  the  temperature  increased.  This  was  to 
see  if  the  xylene  would  be  again  completely  decomposed  to  gas 
and  carbon,  and  to  ascertain,  if  possible,  at  what  temperature 
this  reaction  took  place.  The  runs  made  at  250,270,525,565,400,450 
450  and  470°C  indicated  very  little  reaction  and  practically  no 
change,  or  loss  in  the  xylene.  When  the  temperature  of  complete 
decomposition  was  reached  hydrogen  from  a cylinder  was  intro- 
duced at  various  rates  to  see  if  it  was  possible  to  stabilize  any 
of  the  products  by  means  of  excess  hydrogen  from  another  source. 

The  results  show  that  this  was  in  a small  measure  possible. 

— i 


■ 


33 


TABUS  3. 

Summary  of  runs  over  charcoal  and  deposited  carbon,  which  had 
previously  given  no  condensate.  1000  grams  of  xylene  used  per 
run,  requiring  one  hour.  Hydrogen  introduced  from  cylinder  at 
arbitrary  rate. 


No.  of  Hun 

45 

46 

47 

48 

49 

50 

Gas  introduced 

• » 

• • • • 

H2 

H2 

H2 

Air 

Pressure  (lbs) 

Atm 

. Atm 

21 

25 

15 

5 

Temperature  °C, 

500 

550 

650 

600 

500 

500 

Carb ondi oxide 

0.0 

0.0 

0.0 

0.0 

0.0 

3.5 

Oxygen 

1.0 

0.0 

0.0 

0.0 

0.0 

0.3 

Acetylene 

0.0 

0.7 

6.7 

0.0 

0.5 

0.0 

Ethylene 

0.7 

0.3 

0.1 

0.6 

0.1 

0.1 

Aromatics 

1.2 

1.4 

1.0 

1.0 

1.0 

0.6 

Hydrogen 

82.0 

80.0 

65.6 

67.6 

74.8 

69.9 

Carbon  .Ion oxide 

0.7 

0.1 

0.3 

0.0 

0.0 

5.1 

Ethane 

0.4 

1.9 

0.0 

0.0 

0.0 

4.1 

Methane 

13.6 

13.3 

26.7 

28.7 

21.9 

7.0 

Nitrogen 

0.4 

2.3 

0.0 

2.1 

0.0 

9.4 

Total  gas  cuu»t. 

3.0 

28.0 

25.5 

20.3 

10.0 

1.0 

Percentage  Loss20.0 

100.0 

77.6 

77.0 

30.0 

66.0 

Up  to  105°C 

1.0 

• • • 

2.0 

tr . 

tr . 

• • • 

105  to  130°C, 

• • • 

• ♦ • 

20.4 

23.0 

53.0 

• • • 

130  to  145°C. 

75.5 

• • • 

• • • 

• • • 

17.0 

44.0 

Above  145  C, 

3.5 

• • • 

• • • 

• • • 

• • • 

• • • 

34. 


Huns  45  and  46  corresponded  to  the  results  of  the 
previous  series.  Runs  47,  48  and  49  were  made  under  the  same 
conditions  with  the  exception  that  hydrogen  was  added  from  a cy- 
linder, in  a rapid  stream,  calculated  to  keep  the  atmosphere  in 
the  furnace,  principally  hydrogen.  This  gave  conditions  best 
suited  to  the  formation  of  the  toluene  fraction.  It  would  have 
been  interesting  to  carry  this  investigation  further  under  these 
conditions  hut  so  much  xylene  had  been  decomposed  that  the  furnace 
was  plugging  up  with  deposited  carbon.  At  this  point  8 cubic  feet 
of  air  was  passed  through  the  furnace,  while  heated  to  500° 
to  see  if  some  of  the  carbon  could  be  oxidized  and  thus  removed. 
Several  analyses  were  made  on  the  issuing  gases  and  as  high  as 
12.0$  carbon  dioxide  was  found.  It  was  soon  demonstrated  that 
this  method  of  carbon  disposal  was  too  slow,  so  the  air  was 
discontinued.  Run  No.  50  at  500°C  was  with  pure  xylene,  but  the 
furnace  was  so  filled  up  with  carbon  that  it  required  a pressure 
of  five  pounds,  built  up  from  the  decomposition  of  xylene,  to 
force  any  gas  through.  It  can  be  plainly  seen  that  some  marked 
change  had  taken  place  in  the  furnace.  No  toluene  was  obtained 
and  all  the  condensate  collected  proved  to  be  unchanged  xylene. 

In  other  words,  the  oxygen  and  possibly  the  nitrogen  also,  had 
poisoned  or  slowed  down  the  activity  of  the  furnace.  It  was 
found  by  other  methods  that  charcoal,  after  being  heated  to  the 
nei ghborho od  of  700  C allowed  to  cool,  out  oi  contact  with 
air,  would  take  up  air  very  rapidly.  By  again  heating,  the 
oxygen  came  off  slowly  in  the  form  of  carbon  oxides,  the  dioxide 


• 

. 

• 

. • 

. , 

■ ■ 


. 

« ■ • 

• ' 


. 

, ' • . ' ■ 


• 

■ 

. 

. 

' 

* 

35 


being  given  off  at  lower  temperatures  and  as  the  temperature 
increased,  carbon  monoxide  was  the  chief  product.  It  is  doubtful, 
if  all  the  oxygen  taken  up  could  be  driven  off  at  temperatures  of 
700°C  even  in  the  presence  of  hydrogen.  Diminishing  amounts  of 
moisture,  being  driven  off,  even  after  the  treatment  had  continued 
several  days. 

At  the  end  of  these  runs,  the  furnace  was  so  firmly 
plugged  with  deposited  carbon,  that  it  was  impossible  to  remove 
the  perforated  tube  containing  the  charcoal.  In  fact,  this 
had  to  be  broken  into  pieces  to  be  taken  out  of  the  furnace. 

The  next  series  of  runs  was  made  with  a view  of  increasing 
the  toluene  fraction.  As  before,  charcoal  cubes  were  prepared  and 
placed  in  the  furnace  by  means  of  a tube  made  from  ordinary  brown 
wrapping  paper.  The  gradation  in  size  in  the  charcoal  cubes  was  the 
same  as  previously  and  the  same  quantity  used.  While  heating 
the  furnace,  hydrogen  $as  introduced,  to  try  to  reduce  all  oxides 
at  temperatures  as  low  as  possible.  As  previously,  moisture  and 
a rancid  smelling  liquid  was  driven  off  the  charcoal  as  the 
temperature  increased.  In  this  series  of  runs  the  rate  of  feed 
was  decreased  to  500  gms.  of  xylene  per  hour.  At  lower  temper- 
atures no  appreciable  change  took  place,  and  only  in  the  neigh- 
o _ 

borhood  of  500  C were  any  results  obtained  worth  tabulating. 


36 


Table  4. 

Summary  of  runs  over  2 kilos  charcoal  placed  in  furnace  by 
means  of  paper  tube,  1000  gms.  xylene  used  per  run,  fed  at  the 
rate  of  500  gms.  per  hour.  Furnace  had  been  heated  under  reduc 
ing  conditions.  Results  of  high  boiling  fraction  was  obtained 
from  225  gms.  product  of  the  series. 


No.  of  Run s 

53 

54 

55 

56 

57 

58 

59 

60 

Gas  Introduced 

H2 

H2 

« i • 

• • • 

• • « 

IT 

2 

• • • 

St  earn 

Pressure  Lbs. 

Atm 

Atm 

Atm 

Atm 

Atm 

Atm 

Atm 

Atm 

Temperature  t. 

600 

650 

625 

650 

700 

750 

750 

750 

Carbon  Dioxide 

1.3 

0.5 

110 

0.0 

0.0 

0.0 

0.0 

20.2 

Oxygen 

0.3 

0.1 

0.6 

0.5 

0.1 

0.1 

0.0 

0.0 

Acetylene 

0.3 

0.1 

0.8 

0.3 

0.1 

0.3 

0.2 

0.0 

Ethyl ene 

0.1 

1.5 

1 .1 

0.8 

1.4 

1.5 

1.3 

0.0 

Aromatics 

0.6 

0.8 

3.4 

4.1 

2.2 

1.5 

2.2 

3.8 

Hydrogen 

83.8 

79.0 

50.6 

48.4 

42.2 

44.4 

34.4 

59.0 

Carbon  Monoxide 

1.0 

2.3 

3.9 

1.6 

0.7 

0.4 

0.8 

1.2 

Ethane 

0.0 

0.0 

5.5 

0.0 

0.0 

0.0 

0.0 

0.9 

Methane 

9.1 

16.6 

22.1 

41.5 

48.9 

48.0 

58.8 

12.8 

Nitrogen 

3.5 

0.0 

11.0 

3.0 

6.4 

3.8 

2.3 

2.1 

Total  Gas  Cu.ft. 

5.2 

8.0 

1.5 

3.0 

6.8 

10.2 

10.0 

13.4 

Percentage  Loss 

6.0 

20.0 

12.0 

8.0 

23.0 

25.0 

33.0 

20.0 

Up  to  105°C 

• • • 

1.0 

1.0 

7.0 

7.0 

8.0 

tr 

105  to  130°C 

• « t 

18.0 

40.0 

45.0 

56.0 

43.0 

10.6 

130  to  145°C 

91.0 

66.0 

43.0 

26.0 

5.0 

2.0 

64.4 

Above  145°C 

3.0 

3.0 

8.0 

9.0 

7.0 

14.0 

5.0 

145  to  170°C  12.8 
170  to  225°C  13.3 
225  to  325°C  44.4 
325  to  Coke  20.4 


Coke 


8.8 


37 


The  results,  although  differing  in  many  details,  show 
fair  agreement  with  the  previous  runs.  The  one  striking  differ- 
ence is  that  the  percentage  of  hydrogen  in  the  issuing  gas  is 
approximately  one-half  as  much  as  previously.  In  run  59  the 
hydrogen  was  admitted  slowly  from  the  tank  and  seems  to  have 
materially  increased  the  toluene  fraction.  This  is  in  direct 
contradiction  to  the  results  obtained  by  Cobb  and  Rollings. 

They  found  that  the  presence  of  hydrogen  when  passing  toluene 
through  red-hot  coke,  greatly  increased  the  decomposition  of 
toluene  to  benzene.  Of  course,  there  are  many  other  conditions, 
in  the  two  sets  of  experiments  which  are  vastly  different,  and 
which  play  an  important  part.  Although,  it  may  be  possible 
that  the  largest  percent  of  this  increase  is  due  to  benzene, 
which  was  stabilized  by  the  hydrogen.  In  run  60,  the  steam 
superheated  to  90Q°C  was  admitted  slowly  during  the  run.  The 
total  water  condensed  amounted  to  1020  gms . The  stabilizing 
effect  of  steam  is  very  noticeable,  it  seems  to  have  lessened 
all  the  various  conditions  which  had  been  promoting  decomposition. 

7.  SERIES  OF  RUNS  THROUGH  IRON  FURNACE. 

At  this  stage  of  the  investigation,  it  was  decided  to 
examine  further  the  effects  of  the  iron  surface  of  the  furnace, 
on  xylene.  Up  to  this  point  so  many  contradictory  results  had 
been  obtained,  and  so  many  factors  had  influenced  the  reactions, 
it  was  necessary  to  prove  definitely  what  part  the  iron  surfaces 


. 


36 


took  in  the  reactions.  Accordingly,  the  furnace  was  allowed  to 

cool,  the  cap  removed  and  the  charcoal  withdrawn.  The  furnace 

walls  were  thoroughly  cleaned  with  a wire  brush,  the  cap  replaced 

and  the  furnace  heated  up  while  superheated  steam  was  passing- 

through  it.  The  steam  was  continued  for  some  hours  and  until  the 

o 

furnace  had  reached  a temperature  of  650  0. 


39 


TABUS  5. 

Summary  of  runs  through  the  furnace  without  any  charcoal. 
The  furnace  had  been  heated  to  640°C  while  superheated  steam  was 
passing  through.  500  gms.  xylene  was  used  in  each  run,  which 
required  one  hour. 


No.  of  Hun 

61 

62 

63 

64 

69 

70 

72 

74 

Gas  introduced 

St  earn 

• • • 

*2 

« • • 

• • • 

H2 

H 

2 

C02 

Pressure  lbs. 

Atm . 

Atm. 

Atm. 

Atm. 

Atm, 

35 

140 

Atm. 

Temperature  d 

650 

675 

650 

625 

660 

650 

625 

600 

Carbon  Dioxide 

25.1  > 

1.2 

0.3 

6.4 

0.3 

0.2 

0.3 

53.8 

Oxygen 

0.7 

1.3 

0.2 

1.0 

0.4 

0.2 

0.1 

0.3 

Acetyl ene 

0.0 

0.3 

0.2 

0.4 

0.7 

0.5 

0.2 

0.1 

Ethylene 

1.2 

1.7 

0.2 

0.3 

0.8 

0.2 

0.5 

0.3 

Aroma-tics 

2.5 

10.0 

0.6 

0.1 

0.2 

1.0 

0.7 

0.3 

Hydrogen 

56.3. 

26.8 

74.  7 

82.8 

82.4 

62.9 

55.0 

20.2 

Carbon  Monoxide 

3.0 

1.2 

13.9 

2.5 

5.7 

2.9 

1.0 

19.8 

Ethane 

1.0 

3.8 

2.0 

0.2 

0.0 

0.0 

0.0 

0.0 

Methane 

6 . 6 

50.0 

6.3 

12.7 

9.5 

32.0 

40.8 

5.2 

Nitrogen 

r*-. 

*•  » 

3.6 

3.7 

1.6 

0.0 

0.0 

0.0 

1.3 

0.0 

Total  Gas  cu.ft. 

5.1 

1.5 

13.6 

16.4 

17.0 

12.0 

6.5 

26.5 

Percentage  Loss 

12.0 

10.0 

60.0 

100.0 

100.0 

99.5 

99.5 

55.0 

Up  to  105°C 

• « « 

2.  0 

tr 

• • « 

• • i 

• • • 

105  to  13C°C 

tr 

22.0 

12.0 

• • • 

• • • 

• • • 

130  to  145°C 

86.0 

61.0 

25.0 

tr 

tr 

44.0 

Above  145°C 

2.0 

5.0 

3.0 

• • • 

• • • • 

1.0 

jJv, 


4Q 

In  this  series  of  experiments  many  interesting  details 
are  clearly  demonstrated.  In  run  61  the  protecting  action  of 
steam  is  clearly  shown,  also  the  percentage  of  carbon  dioxide 
is  slightly  greater  than  in  the  case  where  the  furnace  contained 
charcoal.  In  this  case  the  carbon  must  be  coming  from  the  de- 
composed xylene.  In  Ho.  62  the  steam  was  discontinued  and  the 
run  made  at  once  without  any  change  being  made  in  the  furnace 
with  the  exception  of  a slight  rise  in  temperature.  Here  the 
decomposition  of  the  xylene  was  greater  but  the  loss  was  even 
less,  more  going  to  lighter  boiling  products.  Run  63  was  made 

directly  after  62  without  any  change  except  a lowering  of  the 
o 

temperature  25  C.  With  this  run,  hydrogen  from  a cylinder  was 
introduced  in  a slow  stream  intended  to  maintain  reducing  condi- 
tions in  the  furnace,  with  hydrogen,  other  than  that  from  the 
decomposition  of  xylene.  In  former  runs,  it  was  found  that  af- 
ter the  furnace  and  charcoal  had  been  steamed,  and  then  reduced 
to  a certain  degree  by  hydrogen,  that  the  furnace  reached  a 
condition,  which  for  the  sake  of  distinction,  we  might  call 
"activated”.  In  this  condition  the  tendency  was  for  complete 
destruction  of  the  liquid  hydrocarbons  into  hydrogen,  carbon 
and  some  methane.  Run  63  was  made  in  order  to  see  if  this 
activated  condition  could  be  obtained  without  the  presence  of 
charcoal.  When  the  run  was  about  three-quarters  completed,  a 
great  increase  in  the  outcoming  gas  was  noticed  and  the  conden- 
sate gradually  diminished  and  finally  stopped.  When  this  happen- 
ed, the  furnace  temperature  fell  considerably.  After  waiting 
during  thirty  minutes,  run  64  was  made  to  see  if  this  "activated" 


41. 


condition  still  continued,  the  results  are  conclusive. 

The  furnace  was  new  allowed  to  become  cold,  out  of  con- 
tact with  air,  and  after  standing  a few  days  was  opened.  On 
removing  the  deposited  carbon,  which  was  intensely  black  and  fluf- 
fy, it  was  found  to  weigh  870  gms . or  practically  the  theoretical 
amount  possible  from  the  960  gms.  of  xylene  decomposed.  On  fur- 
ther analysis,  however,  the  carbon  was  found  to  contain  approxi- 
mately 11%  iron,  which  was  found  to  be  a mixture  of  the  magnetic 
oxide,  and  other  oxides  along  with  some  fine  particles  of 
reduced  iron.  The  magnetic  oxide,  seemed  to  form  the  largest 
percentage . 

After  thoroughly  cleaning  out  all  carbon  by  means 
of  a wire  brush,  the  furnace  was  heated  up  to  640°C  and 
a series  of  runs  made  to  see  if  it  was  still  activated.  Run 
65  at  635°C  was  made  with  xylene  alone.  The  results  corresponded 
very  closely  with  run  62,  while  runs  66  and  67  at  650  and  675°C 
were  made  with  hydrogen . The  results  were  similar  to  run  63. 

At  this  stage  it  was  decided  to  pass  super-heated  steam  through 
the  furnace  until  fully  oxidized  or  deadened,  then  reduce  some- 
what with  hydrogen  from  a cylinder  and  then  start  another  run. 

Run  68  was  made  at  665°C  and  had  only  been  going  a few  minutes 
when  a sudden  increase  in  the  gas  given  off  was  noticed  and  the 
condensate  ceased.  Run  69  was  made  to  confirm  these  results. 

It  was  now  desirable  to  see  if  any  of  the  products 
of  decomposition  of  the  xylene  could  be  stabilized,  by  means 
of  increasing  the  hydrogen  concentration.  Accordingly,  in  run 
70,  the  furnace  was  placed  under  a pressure  of  35  pounds  per 


* 

. 


, • Hdy.  t 'i,  $ 


■ 


, . 

. 


. 

• . 


. 


42. 


square  inch,  with  hydrogen,  before  the  xylene  was  admitted.  In 
run  72,  the  pressure  with  hydrogen  was  increased  to  140  pounds, 
before  starting,  but  after  the  xylene  was  admitted,  the  decompo- 
sition gases  were  sufficient  to  keep  the  pressure  at  the  desired 
point.  These  two  runs  show  that  it  was  not  possible  to  stabilize 
even  benzene  under  these  conditions.  In  the  next  run  at  600°C 
carbon  dioxide  was  passed  through  slowly  and  so  changed  the  con- 
ditions in  the  furnace  that  much  of  the  xylene  came  through  un- 
changed. The  effects  of  carbon  dioxide  are  somewhat  analogous 
to  those  of  steam  under  similar  conditions.  It  is  possible  the 
carbon  dioxide,  or  more  probably  the  carbon  monoxide,  formed  in 
both  cases,  is  responsible  for  this  inhibition.  This  series 
demonstrates,  that  the  catalyst,  whatever  it  may  be,  appears 
to  possess  the  capacity  for  invigorat ion . It  did  not  prove  what 
this  catalyst  was,  because  even  minute  decompositi  on  of  xylene 
would  deposit  carbon,  and  this  carbon  may  have  promoted  the  de- 
composition reaction,  or  again,  it  may  have  acted  only  as  a 
promoter  to  the  iron  surfaces. 

8.  SERIES  OF  RUNS  THROUGH  COPPER  LINED  FURNACE. 

It  was  considered  more  easy  to  get  rid  of  the  influence 
of  iron  than  of  carbon.  Accordingly  a tube  was  made  from  No.  18 
sheet  copper,  which  fitted  snugly  inside  the  iron  furnace  and 
extended  under  the  ends  of  the  caps.  In  this  manner  all  iron 
surfaces  including  the  thermo  couple  pockets,  were  covered  with 
copper.  The  influence  of  copper  on  the  decomposition  of  xylene 
is  shown  in  table  6.  The  copper  was  oxidized  with  steam  and 
reduced  with  hydrogen  from  the  cylinder  as  in  previous  runs. 


t 


4 

■ 

. • ‘ 

» 

, 

; 

■ 

. 

. 

. 

' 

* 

.. 

, 

1 

. 

. 

, . 


> 

. 

■ 


■ 


* 


TABLE  6 


43. 


Summary  of  runs  through  copper  lined  furnace  500  gms.  of 
xylene  being  used  per  run  per  hour. 


Bo.  of  run 

75 

76 

77 

78 

79 

Gas  introduced 

• • • 

9 • • 

St  earn 

• • 

H. 

Pressure  lbs. 

Atm 

Atm 

Atm 

Atm 

Atm 

Temperature  C 

575 

625 

610 

610 

610 

Carbon  Dioxide 

2.8 

0.7 

17.4 

3.8 

not 

Oxygen 

0.6 

0.3 

2.0 

2.4 

run 

Acetylene 

0.3 

0.4 

0.4 

0.4 

Ethylene 

0.9 

1.2 

1.6 

1.4 

Aromatics 

0.8 

2.4 

2.4 

5.4 

Hydrogen 

69.1 

76.0 

62.8 

40.4 

Carbon  Monoxide 

14.5 

5.2 

4.1 

2.6 

Ethane 

2.7 

2.3 

0.9 

0.0 

Methane 

4.2 

11.1 

8.0 

31.9 

Nitrogen 

4.1 

0.4 

0.4 

11.7 

Total  gas  cu.ft. 

3.  8 

4.7 

3.0 

0.7 

8.5 

Percentage  Loss 

37.5 

32.5 

12.0 

7.5 

12.5 

Up  to  105° C 

0.0 

0.0 

0.0 

0.0 

0.0 

105  to  130°C 

3.0 

5.0 

10.0 

25.0 

7.5 

130  to  145°C 

55.5 

62.5 

75.0 

63 . 6 

76.5 

Above  145  C 

4(,0 

tr 

3.0 

4.0 

3.5 

44. 


These  results  show  that  somewhat  greater  decomposition 
took  place  in  the  copper  than  in  the  iron  furnace.  comparing 

runs  61  and  76,  it  can  he  seen  that  steam  exerted  similar  influ- 
ences in  each  case.  Run  79  was  made  after  reducing  the  furnace 
some  time  with  hydrogen.  It  was  not  found  possible  to  activate 
the  copper  lining  so  that  complete  decomposition  took  place  as 
happened  in  the  case  of  iron.  After  cooling  the  lurnace  v;ab 
opened  and  only  a gram  or  so  of  carbon  was  found  scattered  along 
the  bottom.  In  this  case  it  would  appear  that  the  carbon  had 
disappeared  in  gaseous  form  rather  than  being  deposited.  ihe 
cooper  surface  was  highly  reduced  and  in  a clean  condition. 


45 


TABLE  7. 

Summary  of  runs  through  copper  lined  furnace  containing 
2-g-  kilos  of  charcoal  cubes,  each  run  consisted  of  200  gms.  of 
xylene,  a.nd  was  fed  through  furnace  in  one  hour.  The  percentages 
given  for  the  high  boiling  (above  145)  were  obtained  from  50  gms. 
obtained  in  these  runs. 


No . of  Bun 

81 

82 

83 

84 

85 

86 

88 

Gas  introduced 

• • • 

• • • 

• • • 

• • • 

St  earn 

H2 

Pressure  lbs. 

Atm 

Atm 

Atm 

Atm 

Atm 

Atm 

Atm 

Temperature  0. 

600 

630 

680 

750 

735 

750 

765 

Carbon  Dioxide 

2.9 

1.8 

1.0 

0.8 

20.  7 

2.0 

0.6 

Oxygen 

0.5 

0.4 

0.5 

0.5 

0.6 

1.1 

0.4 

Acetylene 

0.6 

0.2 

0.5 

0.1 

0.3 

0.6 

1.0 

Ethylene 

2.3 

3.5 

1.4 

1.4 

1.4 

1.2 

2.4 

aromatics 

0.5 

2.5 

0.4 

0.7 

1.0 

1.2 

1.6 

Hydrogen 

34.2 

18.2 

36.3 

31.0 

43.7 

36.5 

44.5 

Carbon  Monoxide 

17.9 

27.4 

10.2 

9.6 

16.7 

11.5 

13.8 

Ethane 

10.8 

7.5 

0.0 

0.0 

4.2 

2.0 

0.8 

Methane 

20.0 

30.4 

45.3 

57.2 

9.3 

39.5 

35.0 

Nitrogen 

10.3 

3.1 

4.4 

0.0 

0.8 

4.4 

0.0 

Total  gas  cA-jt. 

1.3 

1.2 

3.3 

3.2 

15.5 

4.5 

4.0 

Percentage  Loss 

25.0 

17.0 

50.0 

70.0 

55.0 

78.0 

63.5 

Up  to  105°C 

2.5 

2.0 

10.0 

10.0 

5.0 

18.0 

18.0 

105  to  13C°C 

25.0 

18.0 

20.0 

15.0 

8.0 

0.5 

12.5 

130  to  145°C 

45.0 

55.0 

15.  0 

0.0 

26.0 

0.0 

0.0 

.bove  145°C 
145  to  170  C 
1 70°C  to  225°C 
225  to  3C0°C 
300  to  400  C 
400  to  Coke 
Coke 

2.5 

45.5 

4.9 

16.5 
21.3 

5.6 
6.2 

8.0 

5.0 

5.0 

6.0 

3.5 

6.0 

46. 


In  this  series  of  runs  no  exceptional  incidents 
were  noticed.  Several  runs  were  made  between  86  and  88  with  and 
without  hydrogen,  in  an  effort  to  get  the  furnace  in  an  activated 
condition  "but  without  success.  Run  88,  with  hydrogen,  indicates 
that  here  the  hydrogen  cut  down  the  actual  loss  "by  stabilizing 

the  lower  boiling  fractions. 

The  next  series  of  runs  were  made,  over  oxidized 
Illium  turnings . These  turnings  had  been  heated  to  800  0 and 
oxidized  by  means  of  oxygen  from  a cylinder.  Three  and  one-half 
kilos  of  oxidized  turning  were  mechanically  mixed  with  small 
pices  of  pumice  stone  and  by  means  of  a paper  tube  were  placed 
inside  the  furnace.  Table  8 summarizes  the  results. 


, 


, 


. 


TABLE  8. 

Summary  of  runs  through  copper  lined  furnace  over  3£  kilos  of 
oxidized  Illiurn  turnings  suspended  in  pumice  stone.  200  grns . xylene 
used  per  run  per  hour. 

High  boiling  percentages  given  from  90  gms.  obtained  in  runs. 


N6.  of  Run 

91 

92 

93 

94 

95 

96 

97 

Gas  Introduced 

• • • 

• • • 

• • • 

• • • 

• « • 

V 

H2 

Pressure  lbs. 

Atra 

Atm 

Atm 

Atm 

Atm 

30 

Atm 

Temperature  C 

525 

600 

650 

700 

785 

785 

785 

Carbond  Dioxide 

not 

6.8 

not 

1.7 

1.3 

0.6 

0.3 

Oxygen 

run 

1.4 

run 

0.8 

0.6 

1.0 

0.1 

.acetylene 

0.8 

1.3 

0.7 

0.8 

0.8 

Ethylene 

4.0 

3.0 

1.8 

1.8 

1.8 

Aromatics 

2.0 

2.0 

2.0 

1.6 

1.8 

Hydrogen 

45.8 

33.7 

36.2 

40.9 

50.2 

Carbon  Monoxide 

5.6 

14.8 

4.2 

4.2 

11.2 

Ethane 

1.9 

1.5 

0.0 

0.0 

0.0 

Methane 

25.3 

37.4 

53.2 

49.1 

34.2 

Nitrogen 

6.4 

3.8 

0.0 

0.0 

0.0 

Total  Gas 

0.2 

0.5 

1 .3 

2.4 

3.5 

4.5 

8.0 

Percentage  Loss 

tr 

3 . C 

15.0 

29.0 

76.0 

88.5 

73.5 

Up  to  105°C 

5.0 

4.0 

tr 

6.0 

7.0 

8.0 

3.0 

105  to  130°C 

3.0 

10.0 

12  .0 

40.0 

7.0 

0.0 

10.0 

130  to  145°C 

84.0 

79.0 

77.0 

17.0 

0.0 

0.0 

6.5 

Above  145°C 

3.0 

4.0 

6.0 

8.0 

10.0 

3.5 

7.0 

145  to  1 70°C 

17.7 

0 

170  to  225  C 

11.1 

225  to  300°c 

16.6 

300  to  400° C 

22.2 

400  to  Coke 

22.2 

Coke 

10.2 

* 


^ — = : — = ffr5! 

The  results  with  Illiurn  oxide,  show  that  in  the  region 
of  700°C  the  decomposition  of  xylene  into  the  toluene  fraction 
is  maximum.  Above  this  temperature  the  lower  boiling  fractions 
decrease  with  a slight  increase  in  the  higher  boiling  compounds. 

It  is  very  probable  that  much  more  interesting  results  would 
have  be  n obtained  by  using  the  Illium  turnings  without  oxidixing. 
The  pieces  of  pumice  when  broken  up,  showed  that  hydrocarbon 
vapors  had  penetrated  them  throughout.  They  contained  very 
fine  particles  of  carbon  in  the  centre  of  even  the  largest  pieces. 

The  next  runs  were  made  to  find  out  the  effects  of 
finely  divided  nickel  under  similar  conditions.  Accordingly 
small  pieces  of  pumice,  about  l/2  inch  square,  were  dipped  in 
heated  nickel  nitrate.  The  nitrate  was  heated  in  a nickel 
crucible  until  most  of  the  water  of  crystallization  was  driven 
off,  and  the  fluid  became  syrupy.  The  cubes  were  then  dried 
at  120°C  for  a few  hours,  placed  in  paper  tube  and  inserted 
into  the  copper  lined  furnace.  The  temperature  was  esse  raised 
to  500°C  and  the  nickel  reduced  with  hydrogen  from  a cylinder. 

Five  pounds  of  nickel  nitrate  was  used.  The  results  are 
given  in  table  9. 


, 


. 

■ 

• 

• 

' 

• 

• 

. 

• 

. 

t 

- 

. 

. 

. 

49 


TABLE  9 


Summary  of 

runs 

using 

nickel 

, which  had 

been 

reduc  ed 

from  the  nitrate, 
per  hour. 

on  pumice 

cubes. 

200 

gms. 

xylene 

used  per  run 

No.  of  Run 

100 

101 

102 

103 

104 

105 

106 

107 

Ga3  Introduced 

• • • 

• • • 

• • • 

• • • 

• • • 

H2 

St  earn 

• • • 

Pressure  lbs. 

Atm 

Atm 

Atm 

Atm 

Atm 

Atm 

Atm 

Atm 

Temperature  °C . 

500 

550 

605 

665 

700 

730 

735 

735 

Carbon  dioxide 

0.8 

0.7 

0.5 

0.7 

0.7 

0.1 

7.0 

not 

Oxygen 

0.0 

0.3 

0.5 

0.7 

0.7 

0.4 

0.4 

run 

Acetylene 

0.0 

1.0 

0.6 

0.9 

0.6 

1.1 

0.7 

Ethyl ene 

0.4 

1.0 

1.7 

2.0 

2.2 

0.7 

1.1 

Aromatics 

0.2 

1.2 

1.0 

1.6 

1.2 

1.2 

1.1 

Hydrogen 

5 7.3 

70.5 

63  .8 

63.3 

53.8 

82.0 

62 . 3 

Carbon  Monoxide 

10.3 

4.6 

5.6 

3.6 

5.0 

2.2 

15.5 

Ethane 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

2.7 

Methane 

23  .9 

21.2 

24.4 

28.6 

33.6 

9.3 

5.0 

Nitrogen 

8.1 

0.0 

1.9 

0.0 

2.2 

3 .0 

4.2 

Total  Gas  Cu.Pt. 

3.2 

3.6 

2.5 

3.0 

3.7 

15.0 

13.2 

8.0 

Percentage  Loss 

64.0 

63.5 

42.0 

49.0 

64  .0 

97.5 

71.0 

98.0 

Up  to  105°C 

• • • 

• • • 

• • • 

2.5 

2.5 

2.5 

• • • 

• • • 

105  to  130°C 

tr . 

tr . 

3.5 

15.5 

19.0 

10.0 

tr 

130  to  145°C 

33.0 

33 . 5 

50.5 

29.0 

9.5 

17.5 

tr 

A.bove  145°C 

3.0 

3.0 

4.  0 

4.0 

5.0 

1.5 

• • • 

50. 


It  is  quite  apparent  that  nickel,  under  these  conditions 
did  not  promote  the  formation  of  high  boiling  compounds  but 
seemingly  promoted  complete  destruction  of  the  condensable  hydro 
carbons.  In  each  of  these  runs  considerable  moisture  was  col- 
lected. Only  small  traces  of  unoxidized  nickel  was  to  be  found 
on  the  pumice. 

The  pumice  resembled  chunks  of  coke  embeded  in  lamp 
black.  The  burning  gas  gave  a distinct  nickel  flame. 

At  the  conclusion  of  this  series  of  experiments  the 
copper  lining  was  found  to  be  in  a poor  state  of  repair.  In  the 
hotter  part  of  the  furnace  it  had  crystallized  and  fallen  to 
pieces  leaving  considerable  surface  of  the  iron  furnace  again 
exposed  to  the  reactions.  Hear  the  ends  some  areas  of  it  was 
found  to  be  highly  reduced  while  mixed  with  these  were  spots 
covered  with  a thick  layer  of  oxide.  It  is  quite  certain  that 
in  the  last  of  the  previous  series  of  runs,  the  iron  surfaces 
were  playing  a part.  The  copper  lining  was  removed  and 

replaced  by  one  of  tinned-copper,  the  tinned  surface  being  on 
the  inside.  This  tube  was  lap-welded  and  riveted  and  made  to 
fit  snugly  into  the  furnace,  covering  all  iron  surfaces. 

9.  SERIES  OF  RUNS  USING  TINNED-COPPER  LINING  IN  FURNACE. 

In  the  preliminary  runs  on  this  lining  the  temperature 
was  not  raised  much  above  605°C,  in  order  to  prevent  scaling  off 
the  tinned  surface.  The  results  are  given  in  Table  10. 


51 


TABLE  10. 

Summary  of  runs  using  tinned-copper  lining  in  furnace. 
2C0  gms.  of  xylene  used  per  run  per  hour. 


No.  of  Run 

110 

111 

112 

113 

Gas  Introduced 

• • • 

• • • 

• • • 

• • • 

Pressure  lbs. 

At  m 

Atm 

At  m 

Atm 

Temperature  C. 

425 

50  0 

550 

625 

Carbon  dioxide 

Not 

2.0 

1.3 

1.0 

Oxygen 

0.7 

1.1 

0.9 

Acetylene 

run 

0.2 

0.4 

1.0 

Ethylene 

1.7 

2.1 

9.2 

Aromatics 

1.0 

5.3 

2.7 

Hydrogen 

71.4 

53.0 

29.4 

Carbon  Monoxide 

6.5 

5.0 

3.6 

Ethane 

0.0 

0.0 

0.0 

Methane 

12.9 

31.4 

58.0 

Nitrogen 

3.5 

0.4 

1.2 

Total  gas  cu.ft. 

0.2 

0.6 

1.0 

1.5 

Percentage  Loss 

12.0 

8.0 

14.0 

2 7.0 

Up  to  105°C 

« • • 

2.5 

2.0 

5.0 

105  to  130°C 

• « • 

tr 

12.0 

25.0 

1.30  to  145 °C 

84.5 

86.5 

69.5 

36.0 

Above  145°q 

3.5 

3.0 

2.5 

7.0 

52. 

These  results  indicate  that  in  the  neighborhood  of 
700°C  a tinned  surface  in  the  furnace  would  be  favorable  for  the 
production  of  toluene  and  benzene  from  xylene. 

The  next  series  of  runs  were  'aade  to  find  out  the  effects 
on  xylene,  of  finely  divided  nickel-oxide  on  charcoal  under 
various  conditions.  The  2-g-  kilos  of  charcoal  cubes,  which  had 
been  used  previously  in  the  copper  lined  furnace,  were  heated 
at  700°C  in  an  atmosphere  of  hydrogen,  allowed  to  cool,  - out  of 
contact  with  air,  - then  dipped  in  a thin  paste  containing  one 
pound  of  nickel  oxide.  After  being  dried  at  110°C  they  were 
placed  in  a paper  tube  and  insetted  in  the  furnace,  in  the  usual 
manner.  In  this  series  the  nickel  oxide  was  not  reduced  with 
hydrogen  before  the  runs  were  started.  The  results  are  tabulated 


in  Table  11 


53 


table  11. 


Summary 

of  runs 

over 

nickel 

oxide 

on  charcoal. 

200  gins. 

of  xylene  used  ; 

per  run 

per  hour.  Tinned 

copper 

lining 

1 in  furnac 

No.  of  run 

120 

121 

122 

123 

124 

125 

126. 

Gas  introduced 

• • • 

• • « 

• • • 

• • • 

• • • 

H2 

Air 

Pressure  lbs. 

Atm 

Atm 

Atm 

Atm 

Atm 

15 

Atm. 

Temperature  C- 

475 

525 

565 

600 

650 

665 

665 

Carbon  Dioxide 

1.0 

0.0 

1.0 

0.8 

0.5 

0.0 

0.4 

Oxygen 

1.0 

0.4 

0.8 

0.9 

0.3 

0.0 

0.5 

Acetylene 

0.1 

0.4 

0.0 

0.1 

0.* 

0.0 

0.0 

Ethylene 

0.3 

0.5 

1.0 

1.0 

0.5 

0.4 

0.9 

Aromatics 

0.3 

0.3 

0.6 

0.7 

0.5 

0.6 

0.5 

Hydrogen 

64.0 

65.4 

67.6 

66 . 8 

80.0 

81.5 

77.3 

Carbon  Monoxide 

8.5 

5.9 

6.4 

8.0 

5.8 

3.4 

5.3 

Ethane 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

Methane 

24.8 

23.6 

18.8 

19.4 

11.8 

14  .1 

15.1 

Nitrogen 

0.0 

3.4 

3.8 

2.3 

0.0 

0.0 

0.0 

Total  Gas  cu.ft 

3.2 

3.9 

4.0 

4.5 

7.0 

9.0 

6.0 

Percentage  Loss 

82.5 

77.5 

63.5 

33.0 

98.0 

100.0 

96.0 

Up  to  105°C 

0.0 

4.0 

tr 

tr 

• • • 

• • • 

tr 

105  to  130°C 

tr 

tr 

6.  0 

9.0 

• • * 

. . . 

tr 

130  to  145°C 

14.5 

13.5 

25.0 

3.0 

2.0 

• • • 

tr 

Above  145°c 

3.0 

5.0 

5.5 

5.0 

• • • 

• • • 

54 

In  each  of  the  above  runs  three  to  five  grans  of  water 
were  collected.  The  combination  of  hickel  oxide  and  charcoal 
gave  results  similar  to  the  iron  oxides  and  charcoal.  Before 
run  125  the  outfit  had  been  reduced  for  one  hour  with  hydro- 
gen under  15  pounds  pressure.  Before  run  126  nine  cubic  feet  of 
air  had  been  passed  through  the  hot  furnace  but  was  dicontinued 
during  run.  When  the  furnace  was  cleaned  after  this  series, 
it  was  found  that  practically  all  the  tin  surface  had  scaled  off 
the  copper  tube.  Thus  copper  as  well  as  tin  could  have  exerted 
an  influence  on  the  last  runs. 


■ 

- 


55 


TABLE  12. 

Summary  of  runs  through  copper  lined  furnace  over  l/2 
pound  of  molybdenum  powder,  mixed  dry  among  small  pieces  of  pumice 


stone.  200  gms. 

of  xylene  used  per 

run  per  hour 

No.  of  run 

130 

131 

132 

133 

134 

Gas  Introduced 

• • • 

• • • 

• • • 

• • • 

H 

2 

Pressure  lbs. 

Atm 

Atm 

Atm 

Atm 

60 

Temperature  fC 

550 

600 

650 

680 

690 

Carbon  Dioxide 

0.9 

0.6 

0.4 

0.6 

0.6 

Oxygen 

1.0 

1.0 

0.4 

0.0 

0.7 

Acetylene 

0.5 

0.3 

0.5 

0.3 

0.4 

Ethylene 

1.8 

0.9 

1.1 

1.1 

0.6 

Aromatics 

5.5 

2.8 

0.3 

1.6 

1.1 

Hydrogen 

5 7.9 

46  .0 

30.9 

33.4 

36.4 

Carbon  Monoxide 

4.2 

10.8 

3.4 

2.2 

2.4 

Ethane 

0.0 

0.0 

0.0 

0.0 

0.0 

Methane 

22.5 

38.5 

59.9 

60.8 

54.6 

Nitrogen 

5.9 

0.0 

3.1 

0.0 

3.2 

Total  gas  cu.ft. 

0.7 

1.8 

3.0 

3.3 

8.0 

Percentage  Loss 

30.0 

30.0 

65.0 

76.5 

81.0 

Up  to  105°C 

0.0 

lost 

15.0 

16.5 

11.0 

105  to  130°C 

5.0 

II 

13.0 

0.0 

0.0 

130  to  145°C 

63.0 

II 

0.0 

0.0 

0.0 

Above  145°C 

2.  0 

3.0 

7.0 

7.0 

8.0 

■U 


56 


This  series  of  runs  was  made  with  the  temperature  of  the 
furnace  gradually  increasing.  In  each  run  four  to  six  grams  of 
water  were  collected.  Molybdenum  promotes  the  decomposition  of 
xylene  to  methane  rather  than  to  hydrogen.  If  the  conditions  were 
favorable  it  should  be  a good  contact  surface  for  the  production 
of  benzene. 

After  completing  the  runs  over  molybdenum  the  furnace 
was  cofcled,  under  an  atmosphere  of  hydrogen,  and  the  carbon  depo- 
sition removed.  ^t  this  time  some  places  in  the  copper  lining 
had  given  away  thus  exposing  a few  small  patches  of  iron  surface. 

The  following  runs  were  made  over  metallic  cobalt  cubes. 
Three  kilos  2 cm. square  and  3 kilos  1 cm. square,  were  placed  in 
a paper  tube  and  inserted  into  the  furnace  in  the  usual  manner. 

The  temperature  was  raised  to  470°C  and  the  whole  outfit  kept 
under  a pressure  of  60  pounds  of  hydrogen  for  two  hours  before 
commencing  the  runs.  Even  after  this  treatment  moisture  was 
collected  in  each  run,  due,  presunably,  to  the  reduction  of 
oxi des. 

The  results  are  given  in  Table  13. 


► - 


* 


*> 

«? 


$ 


Table  13 


Summary  of  runs  over  metallic  cobalt  cubes.  200  gms. 
xylene  used  per  run  per  hour. 


Ho.  of  run 

140 

141 

142 

143 

144 

145 

Gas  introduced 

• • * 

• • • 

« • • 

• • • 

• • • 

H2 

Pressure  lbs. 

Atm 

Atm 

Atm 

Atm 

Atm 

110 

Temperature  °G. 

475 

525 

575 

625 

660 

660 

Carbon  dioxide 

0.9 

0.7 

0.6 

0.4 

0.5 

0.7 

Oxygen 

0.7 

0.1 

0.6 

1.5 

0.6 

0.9 

Acetylene 

0.3 

0.6 

0.2 

0.5 

0.4 

0 . 4 

Ethylene 

1.2 

2.4 

1.5 

1.2 

1.4 

0.9 

Aromatics 

0.8 

1.2 

1.4 

1.3 

1.3 

1.4 

Hydrogen 

80.2 

76.7 

76.7 

72.8 

69.1 

32.3 

Carbon  Monoxide 

3.8 

4.0 

4.6 

1.3 

0.7 

0.4 

Ethane 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

-w-e  thane 

11.0 

12.9 

12.6 

21.7 

26.0 

61.4 

Nitrogen 

1.1 

1.4 

1.8 

0.0 

0.0 

1.6 

Total  gas  cu.ft. 

1.4 

2.3 

3.2 

4.6 

5.4 

5.1 

Percentage  loss 

35.0 

38.0 

45.0 

73.0 

96.5 

90.0 

Up  to  105°C 

1.0 

tr 

2.0 

7.5 

1.5 

8.5 

105  to  130°C 

4.0 

8.0 

29.0 

12.5 

0.0 

0.0 

130  to  145°C 

55.0 

50.0 

20.5 

4.0 

0.0 

0.0 

Above  145°C 

5.0 

4.0 

3.5 

3.0 

2.0 

1.5 

The  general  reactions  of  cobalt  can  be  seen  from  the 
table,  however,  the  influence  of  some  iron  surface,  although 
not  activated  ought  not  to  be  underestimated.  The  tendency  t 


58 


destroy  the  hydrocarbon  rather  than  to  build  it  up 
boiling  compounds  is  evident.  Around  575°C  cobalt 
favor  the  formation  of  toluene. 


into  higher 
appears  to 


Table  14 


59. 


Summary  of  runs,  through  copper  lined  furnace  over  two 
pounds  of  finely  divided  manganese,  scattered  through  small  pieces 


of  pumice  stone. 

2 00  gms . o f 

xylene 

used 

per  : 

No.  of  Run 

150 

151 

152 

153 

154 

(las  introduced 

• • • 

• • • 

• • • 

• • • 

h2 

Pressure  lbs. 

Atm 

Atm 

Atm 

Atm 

80 

Temperature  °G, 

565 

600 

645 

685 

685 

Carbon  Dioxide 

0.3 

0.3 

0.5 

0.4 

0.5 

Oxygen 

0.4 

0.5 

0 . 6 

0.2 

0.5 

Acetylene 

0.5 

0.5 

0.5 

0.5 

0.4 

Ethylene 

2.6 

3.4 

3.1 

1.1 

1.0 

Aromatics 

2.1 

1.3 

0.8 

1.7 

1.4 

Hydrogen 

53.  4 

52.2 

42.6 

48.8 

52.6 

Carbon  Monoxide 

2.9 

0.4 

0.9 

1.2 

1.3 

Ethane 

0.0 

0.0 

0.0 

0.0 

0.0 

-“•ethane 

32.3 

40.4 

51.0 

46.1 

39.6 

Nitr  ogen 

5.5 

1.0 

0.0 

0.0 

2.6 

Total  gas  cu.ft. 

1.2 

2.1 

2.7 

4.2 

6.  0 

Percentage  Loss 

30.0 

44.  0 

50.0 

84.0 

97.0 

Up  to  105°C 

2.0 

4.0 

11.0 

11.0 

3.0 

105  to  13Q°C 

24.0 

30.0 

27.0 

0.0 

• • • 

130  to  145°C 

36.0 

6.0 

0.0 

0.0 

• • • 

Above  145°C 

8.0 

16.0 

12.  0 

5.0 

• • • 

This  series  would  indicate  that  the  presence  of  mangan- 
ese influences  the  partial  decomposition  of  xylene  at  lower 


60 


temperatures  than  the  previous  metals.  In  the  neighborhood  of 
600°C  the  high  boiling,  as  well  as  the  low  boiling,  products 
are  maximum;  also  the  ethylene  content  of  the  escaping  gas  is 
highest.  Again,  the  influence  of  the  snail,  exposed,  iron  sur- 
faces of  the  furnace  and  also  the  copper  lining  must  be  taken 
into  c onsiderati on . Some  traces  of  water  were  noticeable  in 
these  runs. 


. 

L ■ , ■'  : ■ ;fr  ' 

.•  . ■ ■ ■ • ' 

f: 


j 0 :j|«  ' ' " 


> 


TABLE  15 


Sumaiary  of  runs  made  through  copper  lined  furnace,  over 
440  gins,  of  aluminum  powder  scattered  through  small  pieces  of 
pumice.  200  gins,  of  xylene  used  per  run  per  hour. 


No.  of  Run 

160 

161 

162 

163 

165 

Gas  introduced 

• • • 

• ♦ • 

• • • 

• • • 

H2 

Pressure  lbs. 

Atm 

Atm 

Atm 

Atm 

70 

Temperature  °C. 

525 

550 

600 

680 

700 

Carbon  Dioxide 

0.2 

0.4 

0.6 

0.4 

0.4 

Oxygen 

0.1 

0.3 

0.9 

0.7 

0.4 

Acetylene 

0.3 

0.3 

0.5 

0.3 

0.2 

Ethylene 

2.  0 

2.7 

2.0 

1.5 

1.1 

aromatics 

1.8 

1.6 

1.3 

1.0 

1.1 

Hydrogen 

74.0 

73.4 

76.7 

72.5 

80.5 

Carbon  Monoxide 

1.6 

1.5 

0.8 

1.0 

0.8 

Ethane 

1.7 

0.5 

0.0 

0.0 

0.0 

Methane 

12.5 

16.3 

17  .2 

22.6 

15.5 

Nitrogen 

6.2 

3.0 

0.0 

0.0 

0.0 

Total  gas  cu.ft. 

0.9 

1.5 

4.3 

5.0 

0.4 

Percentage  Loss 

15.0 

25.0 

65.0 

90.0 

96.0 

Up  to  105°C 

1.0 

0.0 

0.0 

0.0 

4.  0 

105  to  130°C 

8.0 

4.0 

10.0 

8.0 

• « • 

130  to  1 45°C 

70.  0 

67.0 

22.0 

0.0 

• 4 • 

Above  145°c 

6.  0 

4.0 

3.0 

2.0 

• • • 

Some  water 

was 

collect' 

ed  in 

all  these  run 

exception  of  number  163  and  165.  When  cleaning  the  furnace 


•v  • 

■v 

t 


62. 

after  completing  this  series  the  copper  lining  w as  found  to  be 
broken  in  so  many  places,  exposing  the  iron  surface,  that  it  was 
decided  to  remove  it. 

10.  SERIES  OF  RUMS  USING  REFRACTORY  LINING  IN  FURNACE. 

The  furnace  was  cleaned  by  means  of  a wire  brush, heated 
to  600°C  and  kept  under  100  pounds  pressure  with  hydrogen,  for 
some  hours,  to  reduce  any  adhering  oxide.  It  was  then  cooled, 
under  an  atmosphere  of  hydrogen,  again  cleaned  with  the  wire 
brush,  and  then  coated  by  means  of  a brush,  with  a thin  paste 
made  by  mixing  80  per  cent  of  Hytempite  with  20  percent  Alundum 
cement.  This  coating  was  allowed  to  air  dry  before  a second 
coating  was  put  on.  The  furnace  was  then  heated  to  500°C  and 
some  runs  made  to  find  out  the  effects  on  xylene  under  non-metal- 
lic  conditions.  The  results  are  given  in  table  16. 


„ 


■ 

. 

• 

. 

, 

< 

' . 

4 

' 

• 

. 

• 

' 

63 


Table  16. 

Summary  of  runs  using  refractory  lined  furnace.  200  gms. 
xylene  used  per  run  per  hour. 


No . of  Run 

166 

167 

168 

Gas  Introduced 

• « « 

• • • 

• • • 

Pressure  lbs. 

Atm 

Atm 

Atm 

Temperature  C. 

500 

550 

600 

Carbon  Dioxide 

1 . 5 

0.6 

1.0 

Oxygen 

6.1 

5.3 

0.4 

Acetylene 

0.5 

0.7 

0.6 

Ethylene 

2.8 

4.2 

4.4 

Aromatics 

1.8 

4.1 

1.8 

Hydrogen 

55.  4 

22.1 

25.  6 

Carbon  Monoxide 

0.6 

0.3 

2.4 

Ethane 

0.0 

0.0 

9.0 

m ethane 

13.0 

25.8 

42.6 

Nitrogen 

18.3 

36.9 

12.2 

Total  gas  cu.ft. 

0.2 

0.4 

1.0 

Percentage  Loss 

25. C 

14.0 

25.  0 

Up  to  105°C 

1.0 

1.0 

Lost 

105  to  130°C 

5.0 

9.0 

II 

130  to  145°C 

66.0 

71.0 

II 

Above  145  C 

3.0 

5.0 

12.0 

After  completing  this  series  the  furnace  was  cooled  and 
opened.  In  a few  places  small  patches  of  refractory  had  fallen 


64. 


off  the  furnace  wall.  Directly  under  these  places  were  found  small 
mounds  of  carbon , apparently  due  to  the  decomposition  of  xylene 
by  the  exposed  iron  surface. 

The  furnace  was  cleaned  of  all  deposited  carbon  and  again 
coated  with  the  refractory  paste.  This  was  to  make  certain 
that  all  iron  surfaces  were  covered  before  commencing  a new 
series  of  runs.  A cylinder  of  ethylene,  put  on  the  market  by  The 
United  States  Industrial  Chemical  ^o., Curtis  Bay .Baltimore , under 
the  trade  name  of  ’'Calorene"  had  been  secured  to  use  in  these 
runs.  In  previous  experiments  it  had  been  noticed,  that  when 
the  outgoing  gas  contained  any  appreciable  amount  of  ethylene, 
the  condensate  contained  larger  amounts  of  the  higher  boiling 
products.  In  this  series  the  aim  was  to  obtain  the  maximum 
percentage  of  these  high  boiling  compounds.  Also  to  determine, 
if  possible,  if  by  definite  control  of  the  atmosphere  within 
the  furnace,  the  desired  end  products  could  be  obtained.  In 
other  words,  it  was  decided  that  certain  definite  conditions  in 
regard  to  temperature  and  contact  surfaces  were  necessary  to 
practically  deco.npose  the  xylene  molecule,  regardless  of  the 
end  products  obtained  and,  that  the  reaction  could  be  driven, 
by  mass  action,  to  yield  the  products  desired.  That  is, 
if  the  furnace  was  in  a proper  condition  to  decompose  xylene 
freely,  but  not  too  streneously,  that  by  keeping  the  atmosphere 
in  the  furnace  mostly  hydrogen,  benzene  could  be  obtained  as  an 
end  product;  while  if  the  atmosphere  in  the  furnace  was  mostly 
ethylene,  the  end  products  would  likely  be  higher  boiling  confounds 
The  results  are  shown  in  Table  17. 


. 

. 


* 


■ 


. 

. 


1 

. 

. 

. ■ ; 

. 

; • 4 

■ 

. 

• c- 

, 

< 

t 

P H 


*l  \ 

..  . • • '•  ; . 

,,, 


65 


Table  17. 

Summary  of  runs  through  refractory-lined  furnace,  without 
any  other  contact  surface,  using  calorene  or  hydrogen.  200  grns. 
xylene  used  per  run  per  hour. 


No.  of  Run 

183 

184 

185 

186 

187 

188 

189 

190 

Gas  Introduced 

c2h4 

C2H4 

c2h4 

c2h4 

H2 

h2 

C2H4 

c2h4 

Pressure  lbs. 

45 

45 

45 

Atra 

150 

125 

45 

90 

Temperature  C. 

500 

550 

6 00 

610 

615 

650 

670 

710 

Carbon  Dioxide 

0.0 

0.6 

0.4 

0.4 

0.0 

0.5 

0.3 

0.0 

Oxygen 

0.0 

0.4 

0.5 

0.3 

0.1 

0.2 

0.4 

0.0 

Acetylene 

■ 0*1 

0*4 

1*0 

0.7 

0.2 

0.3 

0.9 

0.0 

Ethylene 

53.4 

9.0 

3.5 

31.1 

0.4 

0.5 

2.6 

1.5 

Aromati C3 

0.7 

1.3 

1.9 

0.6 

0.4 

0.6 

1.3 

1.2 

'Hydrogen 

2.0 

8.6 

6.7 

4.  0 

60.0 

58.  7 

6.0 

28.8 

Carbon  Monoxide 

3.5 

4.9 

3.3 

3.1 

4.0 

5.2 

4.4 

6 .8 

Ethane 

12.7 

7.4 

8.6 

22.8 

0.0 

0.0 

0.0 

0.0 

Methane 

23.0 

67.4 

73.3 

37.0 

34.9 

35.7 

84.1 

62.3 

Nitrogen 

0.0 

0.0 

0.7 

0.0 

0.0 

0.0 

0.0 

0.0 

Total  gas  cu.ft 

• 1.3 

0.8 

0.5 

10.0 

6.5 

7.4 

0.4 

4.3 

Percentage  Loss 

+1.0 

22.0 

34.0 

2 7vU~‘ 

26.0 

37.5 

75.0 

67.5 

Up  to  105°C 

tr . 

7.5 

18.5 

tr 

69.0 

55.5 

10. 0 

17.0 

105  to  130°C 

3.0 

24.0 

4.0 

0.0 

0.0 

0.0 

0.0 

0.0 

130  to  145°C 

79.0 

16.5 

0.0 

0.0 

0.0 

0.0 

0.0 

0.0 

Above  145°C 

18.0 

30.0 

43.5 

77.7 

5.0 

7.0 

15.0 

15.5 

The  fir 

st  runs 

of  this  series  were  made 

at 

350,400 

,415, 

450  and  475°C. 

They  were  all 

. made 

under 

a pres 

sure 

of  45 

pounds 

* 


V < 


f < t 


66 


built  up  by  ethylene  from  the  cylinder.  At  these  temperatures 

there  was  very  little  decomposition  of  xylene,  ranging  from  two 

to  eight  percent,  the  majority  going  into  higher  boiling  compounds. 

In  each  of  these  runs,  however,  there  was  a gain  in  weight,  from 

one-half  to  one  and  one-half  per  cent  of  the  original  xylene.  This 

was  found  to  be  due  to  dissolved  ethylene,  which  was  driven  off 

again  when  fractionating  the  condensate.  Another  significant 

result  shown  by  the  gas  analysis  was  the  stability  of  ethylene 

o 

under  these  conditions.  At  415  C the  waste  gas  contained  89.4 

percent  ethylene,  no  ethane  and  8.5  percent  methane;  while  at 

475°C  it  contained  73.9  percent  ethylene,  4.6  percent  ethane 

o _ 

and  8.0  percent  methane.  At  500  C the  maximum  percentage  of 
ethane  was  obtained  while  the  percentage  of  methane  increased 
with  temperature. 

In  all  the  runs  with  ethylene,  it  was  necessary  to 
conserve  the  gas  as  much  as  possible,  so  that,  when  running  under 
45  pounds  pressure,  the  waste  gas  was  allowed  to  escape  slowly, 
otherwise  no  ethylene  could  be  added  because  the  decomposition 
gas  kept  the  pressure  increasing.  Run  184  indicated  that  the 
conditions,  where  all  the  xylenes  were  being  decomposed  were 
being  approached.  Run  185  showed  the  optimum  temperature 
was  in  that  neighborhood,  also  that  the  conditions  were  favorable 
for  the  formation  of  high  boiling  compounds.  At  this  tempera- 
ture ethylene  was  found  to  decompose  rapidly  the  majority  going 
to  methane.  ITow  for  the  building  up  of  high  boiling  compounds 
the  larger  the  excess  of  ethylene  in  the  furnace  the  better, 


6? 


therefore  in  run  186,  the  pressure  was  reduced  to  4 or  5 pounds, 
and  the  ethylene  passed  into  the  furnace  in  a very  rapid  stream. 
In  this  manner  the  products  were  driven  through  the  furnace 
faster  than  usual,  without  allowing  the  decomposition  of  the 
products,  or  more  especially  of  the  ethylene,  to  become  complete. 
This  run  gave  the  maximum  yield  of  high  boiling  compounds . 

At  this  point  it  was  desirable  to  find  out  if  these 
particular  conditions  were  favorable  for  forming  lower 
boiling  hydrocarbons  and  if  they  could  be  stabilized  and  recover- 
ed. Hun  187  gave  conclusive  evidence  that  this  was  possible.  It 
is  interesting  to  analyze  these  results  a little  farther.  The 
yield  of  69.0  percent  is  calculated  from  the  weight  percent 
of  the  original  xylene  used.  By  referring  to  the  equation, 

CgHj0+  3 *==*  3 CH4+  OqHq  we  see  that  69.0  percent  by 

weight  equals  93.8  percent  of  the  possible  theoretical  yield 
of  benzene.  The  remainder  of  these  runs  demonstrate  that  the 
optimum  temperature  for  the  desired  results  is  in  the  neighbor- 
hood of  600°C.  At  the  higher  temperatures  the  water  collected 
appeared  to  increase  slightly. 

When  the  furnace  was  opened,  after  cooling,  the  >whdLe 
interior  was  coated  with  a fluffy  layer  of  carbon,  which  was 
very  different  in  appearance  from  previous  deposits.  It  was  a 
metallic  gray  color  and  granular  or  sandy,  while  the  other 
deposits  had  been  intensely  black  and  amorphous.  It  was  evenly 
distributed  along  the  walls  of  the  furnace, even  where  no  iron 
was  exposed.  In  previous  cases  the  deposits  were  directly 


, ' • • ' ■ ■ : 


“ .... 


■ • 


■ . -cr 

. 

y.  . J •-  • ; j.i  X.  • 1 ■ '• 

■ * 


- . r • 


\ ’ r . . \ 


■ . , j.  ' 


i 


. 


. 


68 


opposite  the  exposed  iron  surfaces.  It  does  not  seem  possible, 
that  the  very  small  amount  of  iron  exposed  could  have  been  re- 
sponsible for  all  the  carbon  deposited,  however,  it  may  have 
started  the  reactions  which  were  carried  along  by  the  carbon 
thus  deposited. 

The  next  series  of  runs,  after  cleaning  the  furnace 
entirely  free  from  carbon,  were  made  with  some  small  patches 
of  iron  exposed.  This  was  calculated  to  promote  the  decomposi- 
tion of  xylene  at  lowered  temperatures  and  thus  allow  a better 
yield  of  high  boiling  compounds.  Table  18  shows  that  this  was 
only  partially  successful. 


■ . 


* 


. 


•:v 


>1 

■ 


69 


Table  18. 

Summary  of  runs  through  refractory  lined  furnace  with 
some  iron  surface  exposed.  200  gras,  of  xylene  used  per  run, 
the  time  of  feed  varied  from  5 minutes  to  four  hours. 


No.  of  Run 

200 

203 

205 

207 

208 

210 
St  earn 

211 

212 

Gas  Introduced 

C2H4 

C2H4 

C2H4 

c2h4 

St  earn 

C2H4 

C2H4 

c2h 

Pressure  lbs. 

45 

125 

140 

60 

Atm 

Atm 

145 

75 

Tenperature  °G. 

525 

490 

580 

620 

615 

585 

525 

460 

Carbon  Dioxide 

1.1 

0.4 

0.0 

0.0 

0.6 

1.4 

0.6 

not 

Oxygen 

0.2 

1.8 

0.3 

0.2 

0.5 

0.5 

1.7 

run 

Acetylene 

0.5 

0.7 

0.3 

0.3 

0.5 

0.5 

0.5 

Ethylene 

21.8 

25.1 

5.1 

1.6 

6.2 

33.0 

13.0 

Aromatics 

1.0  ' 

0.6 

0.8 

0.3 

0.5 

0.6 

0.0 

Hydrogen 

13.  4 

7.2 

6.6 

39.5 

43.3 

30.9 

2.0 

Carbon  Monoxide 

4.2 

3.1 

2.3 

2.6 

1.6 

1.1 

4.5 

Ethane 

30.9 

21 .9 

8.3 

8.0 

0.0 

0.0 

15.1 

Methane 

26.9 

33.0 

75.3 

47.5 

45.  S 

32.  0 

60.4 

Nitrogen 

0.0 

6.2 

1.0 

0.0 

0.2 

0.0 

2.2 

Total  Gas  cu.ft. 

2.5 

2.4 

5.2 

14.6 

2.4 

3.1 

12.2 

12.5 

Percentage  Loss 

20.0 

9.0 

25.0 

87.5 

24.0 

30.0 

75.0 

27.5 

Up  to  105°C 

1.5 

1.0 

6.0 

12.5 

tr 

tr 

Lbs  t 

20.0 

105  to  130°C 

10.0 

10.0 

20.0 

• • • • 

25.0 

20.0 

»» 

4.0 

130  to  145°C 

53.5 

22.0 

14.0 

• i • • 

44.0 

40.0 

H 

41.0 

Above  145  C 

15.0 

58.0 

35.0 

tr . 

7.0 

10.0 

7.5 

7.5 

These  runs  were  made  under  what  might  be  termed  extreme 
conditions,  to  find  out  if  any  favorable  condition  such  as  pressur? 
duration  of  time  of  contact  and  mass-action  equilibrium  had  been 
neglected  in  previous  runs. 


j 


?o. 

Run  300  was  fed  at  the  rate  of  one  drop  per  second.  This 
was  to  allow  ample  time  for  equilibrium  to  be  obtained  among  the 
gases  in  the  furnace.  The  decomposition  was  not  excessive  but 
the  most  interesting  feature  brought  out  is  the  percentages  of 
ethylene,  hydrogen,  ethane  and  methane  in  the  issuing  gases.  In 
run  301  the  300  gms.  of  xylene  was  fed  in  ten  minutes.  Here 
the  recovered  products  were  of  equal  weight  to  the  xylene  used. 
The  ethylene  was  fed  in  an  atmospheric  pressure  and  quite  rapid- 
ly. Only  40  percent  of  the  xylene  used  was  changed,  it  going 
almost  equally  into  high  and  low  boiling  compounds.  In  run  303 
the  xylene  was  fed  intermittently,  while  the  ethylene  was  fed 
continuously  at  atmospheric  pressure.  A marked  increased  in 
the  high  boiling  constituents  was  noticeable.  In  run  303  the 
feed  interval  was  about  thirty  minutes.  This  contact  period 
seemed  favorable  for  building  up  the  high  compounds.  In  run 
311  the  rate  of  feed  was  80  drops  of  xylene  per  minute:  while 
in  all  the  other  runs  the  former  feed  rate  of  300  grams 
per  hour  was  used.  In  runs  306  and  307  the  furnace  became  acti- 
vated in  such  a manner,  that  regardless  of  how  fast  or  under 
what  pressure  ethylene  was  added,  all  the  hydrocarbons  were 
decomposed  to  gas  and  deposited  carbon.  In  fact,  it  was  very 
similar  to  the  previous  mentioned  activated  conditions.  The 
introduction  of  superheated  steam  caused  similar  effects  as 
previously.  The  experiments  with  xylene  were  discontinued 
after  run  313.  When  the  furnace  was  opened  the  deposited  carbon 
had  a very  peculiar  formation.  It  was  suspended  from  the 
top  of  the  furnace  in  -leag  fibres  from  one  to  two  inches  long. 


• - 


. 

■ 


. 

5 ; • ” 

t ,,  < 

. 

. 

; . A 


. 

; 

. 


- 


. 


71. 


They  might  be  said  to  resemble  in  shape,  delicate  stalactites. 

The  large  increase  in  the  yield  of  the  high  boiling  hydro- 
carbons, obtained  in  the  last  two  series  of  runs,  made  it  seem 
profitable  to  fractionate  them  further.  The  results  are  given 
in  Table  19. 


. ' . t . . I 

• 

. 


72 


Table  19. 

Fract ionation  of  high  boiling  products  obtained  from  the 
decomposi tion  of  xylene.  The  precentages  given  in  (A)  were  obtained 
on  16b  grams  of  high  boiling  product  obtained  in  the  series  of 
runs  tabulated  in  table  17.  The  results  given  in  (b)  are  from 
325°  of  high  boiling  product  obtained  from  the  series  last 
tabulated . 


Boiling  range 

A 

B 

Sp.Gr.  .15. 5° 0. 

Remarks 

145 

to 

175°C. 

11.5 

6.6 

0.8911 

Light  greenish  oil 

175 

to 

200°C. 

• « • • 

8.9 

0.9057 

Light  oil, at  zero-solid 

200 

to 

225°C. 

23.1 

4.8 

O>.9605 

Darker  oil, at  zero-solid 

225 

to 

240°C. 

5 .8 

7.2 

0.9888 

ii  it  n n it 

240 

to 

255°C. 

12.7 

8.3 

1.0087 

High  oil  with  white  " 

255 

to 

300°C, 

8.0 

15.1 

1.0232 

Oil  - shade  darker 

300 

to 

350°C. 

19.3 

23.4 

1.0625 

ii  n ii 

350 

to 

400°C 

0 

8.0 

14.5 

1.1032 

Reddish  oil  with  yellow 

solid 

400 

to 

500  C. 

7.0 

7 .1 

Solid 

" yellow  solid 

500 

to 

coke 

4.5 

4.0 

It 

Td-h 

Crude  oil.  1.0808 

These  results  show,  that  in  the  last  series  where  greater 
pressures  were  used,  the  higher  boilign  products  contained  a 
larger  percentage  of  solids.  In  each  of  these  series  the  final 
residue  or  coke  amounted  to  about  4%  of  the  high  boiling  product. 


73 


11.  SERIES  OP  RUNS  USING  BENZENE. 

The  runs  on  benzene  were  made  through  the  iron  furnace 
containing  2-g-  kilos  of  charcoal.  The  purpose  being  to  try  to  check 
Cobb  and  Hollings  ' results.  They  found  that  benzene,  while  passing 
through  coke  heated  to  800°C  could  be  entirely  stabilized  by  means 
of  excess  hydrogen.  In  these  experiments  it  was  found  that  when  the 
charcoal  and  furnace  was  activated,  that  it  was  impossible  to 
stabilize  the  benzene  even  at  500°C.  Pressures  as  high  as  125 
pounds  of  hydrogen  per  square  inch  were  used.  On  the  other  hand, 
if  the  charcoal  and  furnace  had  been  treated  with  superheat ed- 
steam,  air  or  carbon  dioxide,  that  the  benzene  could  be  entirely 
stabilized  at  temperatures  as  high  as  800°C  with  a very  small 
pressure  of  hydrogen.  The  condensation  products,  other  than 
recovered  benzene  were  not  analysed. 

12.  SERIES  OP  RUNS  USING  TOLUENE. 

Cobb  and  Hollings  had  found,  that  when  toluene  was  passed 
through  red  hot  coke,  that  it  was  nore  stable  alone  than  when  in 
the  presence  of  hydrogen.  That  is,  hydrogen  caused  the  decompo- 
sition of  toluene  to  benzene  and  methane.  In  run  58,  Table  4, 
hydrogen  was  found  to  increase  slightly  the  toluene  fracti on .Pur e 
toluene  was  run  under  similar  conditions  and  it  was  found  that 
toluene  was  somewhat  more  stable  in  the  presence  of  hydrogen. 

In  cases  where  the  furnace  was  activated  the  toluene  was  entirely 
destroyed  with  or  without  hydrogen. 


. • ■ • 


Jr*-* 


r 


\ 


74 


15.  SERIES  OF  RUNS  USING  NAPHTHALENE. 

In  making  the  runs  on  napthalene,  it  was  preheated  in  an 
electrical  retort,  connected  to  the  top<  end  of  the  furnace  and 
the  vapors  carried  into  the  furnace  by  means  of  the  gasses  bubbled 
through.  The  products  obtained  have  not  all  been  identified  but 
the  analysis  of  escaping  gas  is  interesting. 


75 


Table  20. 

Summary  of  runs  over  2-g-  kilos  of  charcoal  in  iron  furnace, 
with  preheated  napthalene,  carried  into  the  furnace  by  means  of 
gases.  300  gins,  of  napthalene  used  per  run,  at  atmospheric  pre- 
ssure . 


No.  of  Run 

220 

221 

222 

223 

224 

225 

Carri er  gas . 

C°2 

CO 

CO 

H 

2 

N 

2 

CO 

t 

Pre-heat  T emperature°C 

- 340 

320 

340 

330 

330 

325 

Furnace  Temperature°C. 

780 

525 

635 

660 

640 

815 

Gas  used  cu.ft. 

2.6 

2.4 

3.5 

3.2 

1.4 

2.0 

Gas  recovered  cu.ft. 

2.6 

0.4 

2.6 

1.4 

0.9 

1.7 

Percentage  loss 

+ 0.5 

67,5 

22.0 

28.0 

33.3 

65.0 

Carbon  dioxide 

36.0 

17.7 

34.8 

2.9 

1.2 

2.8 

Oxygen 

4.4 

5.2 

2.0 

2.6 

0.8 

1.6 

Acetylene 

0.2 

0.3 

0.5 

0.4 

0.1 

0.3 

Ethyl ene 

0.0 

0.0 

0.3 

1.0 

0.2 

0.4 

Aromatics 

0.1 

0.0 

0.3 

0 .0 

0.1 

0.4 

Hydrogen 

34.8 

38.2 

21.6 

85  .1 

6.1 

72.0 

Carbon  monoxide 

14.8 

17.3 

35.6 

1.4 

2.2 

22.5 

Ethane 

3.0 

2.  8 

I . 8 

0.4 

0.2 

0.0 

Methane 

5.5 

0.2 

0.2 

0.6 

0.3 

tr 

Nitrogen. 

2.2 

18.3 

2.6 

5.6 

88.8 

0.0 

In  the  runs  on  naphthalene  it  was  noticed  that  practical 
ly  as  soon  as  the  run  commenced  the  temperature  of  the  furnace 
dropped.  Even  when  the  current  passing  through  the  heating 
elements,  was  materially  increased,  the  temperature  fell  slowly. 


76 


This  would  indicate  the  reactions  taking  place  inside  the  furnace 
was  absorbing  considerable  heat.  Another  feature, part i cularly 
noticeable  in  the  nitrogen  run,  was  that  the  gas  recovered  did  not 
equal  the  amount  passed  into  the  furnace  from  the  cylinder , even 
with  the  addition  of  the  gas  from  decomposition  of  the  napthalene. 
The  charcoal  may  be  partly  responsible  for  this  result. 

In  the  runs  using  carbon  dioxide  as  the  carrying  gas, 
the  product  contained  a heavy,  black,  high  boiling  oil,  some  free 
carbon,  and  a very  light,  fluffy,  red  material  with  very  little 
odor  of  napthalene.  With  hydrogen  thfe  product  was  dark  gray  con- 
taining also  traces  of  the  light  reddish  material.  The  product 
from  the  nitrogen  rims  was  a compact  greenish  color  and  from 
carbon  monoxide  the  reddish  fluffy  material  formed  the  bulk  of  the 
recovery. 

III.  SOME  PRODUCTS  SYNTHESISED  IN  THE  INVESTIGATION. 

A few  of  the  products,  obtained  in  this  investigation, 
require  rather  streneous  mental  gymnastics  to  explain  their  forma- 
tion. Prom  the  kinetic  theory,  the  intermolecular  collisions, 
which  increase  with  rise  in  temperature,  would  account  for  the 
rupture  of  bonds  or  forces  which  hold  together  atoms  or  groups. 
Also  under  like  conditions  the  larger  molecules,  - higher  boiling 
compounds,  - would  have  a greater  momentum  than  the  smaller  ones, 
and  on  this  account  at  the  instant  of  impact,  would  be  subjected 
to  greater  strain.  That  is,  at  higher  temperatures,  benzene 
should  be  no  re  stable  than  toluene  cr  xylene;  or  to  obtain 
toluene  from  xylene  lower  temperatures  would  be  more  favorable. 


, • 

. 


' 


; < 


. 


( , ■ 


. 


. 


' 


. 


■ > ; • 


77 


The  process  of  decomposition  of  hydrocarbons  can  never  be 
regarded  as  a simple  effect  of  heat  independent  of  the  gaseous 
atmosphere  in  which  it  is  conducted  and  the  way  in  which  we  hope 
to  modify  the  results  of  decomposition  in  various  directions  is  by 
the  deliberate  control  of  that  atmosphere.  The  gaseous  products 
obtained  in  these  experiments  are  extremely  important  and  play  as 
important  a part  in  the  final  products  as  the  gas  introduced.  Their 
effects  can  be  considered  from  two  standpoints .mechanical  and 
chemical.  An  inert-gas,  like  nitrogen,  would  not  enter  directly 
into  chemical  reaction  under  these  conditions,  but  would  play  a very 
important  part  by  washing  the  products  of  decomposition  from  the 
surface  of  the  contact  mat erial , assist  their  volotilization  by 
lowering  their  concentration  in  the  vapor  phase,  and  hurry  them 
away  from  the  region  of  decomposition.  In  the  case  of  hydrogen, 
being  much  lighter,  it  has  a greater  diffusing  power, the  mole- 
cules travel  at  a higher  speed  and  thus  penetrate  small  areas 
where  the  larger  gas  molecules  never  reach.  The  all-important 
action  of  hydrogen,  however,  is  chemical . It  tends  to  reduce 
the  single  ring  benzene  compounds  to  benzene  itself.  A similar 
action  may  be  inferred,  as  is  very  probable,  on  the  attached 
groups  of  more  complicated  ring  compounds,  resulting  in  the 
formation  of  napthalene  and  anthracene.  It  seems  that  this  was 
the  part  played  by  hydrogen  in  the  majority  of  the  experiments 
carried  out.  However,  other  factors  must  be  able  to  modify  this 
tendency  of  hydrogen  because  in  the  experiments  giving  the 
largest  yields  of  the  toluene  fraction,  it  was  found  possible 
to  increase  this  fraction  by  introducing  hydrogen  from  a cylinder, 
although  it  was  not  definitely  proven  that  this  increase  was  not 


•>  .. 


, 

( 

• . • 

, 

, 

■ 

» 

. 

. 

. 

. 

, 

' ■ 


.. 


• 

■ 

- 

V ' T 

• 

■ 

• 

7a 


due  to  benzene. 

It  was  possible  to  change  the  production  of  hydrogen  in 
these  experiments  by  changing  the  temperature,  or  the  activity  of 
the  furnace. 

Methane  could  also  be  produced  in  varying  quantities,  de- 

24 

pending  upon  the  furnace  conditions.  Bone  and  Coward  concluded 
that  methane  decomposes  chiefly,  directly  into  hydrogen  and  car- 
bon, the  process  being  reversible  and  a surface  phenomenon  at 
least  up  to  1200°C.  At  the  temperature  these  experiments  were 
run,  methane  is  practically  stable  and  its  chemical  reaction  would 
be  negligible  but  its  mechanical  action  would  be  very  important 
as  in  the  case  of  nitrogen. 

The  carbon  dioxide  formed  was  in  small  quantities  and 
was  always  in  equilibrium  with  carbon  nonoxide.  They  seemed  to 
deaden  orpoison  the  activity  of  the  f or nace, although  it  is  pos- 
sible they  caused  partial  combustion. 

Acetylene  was  formed  in  small  quantities  and  although  many 
investigators  claim  that  the  building  up  process  is  through  the 
ability  of  acetylene  to  polymerize,  it  was  concluded  from  these 
experiments,  that  acetylene  played  a very  small  part.  At  higher 
temperatures,  it  was  more  liable  to  be  decomposed  to  carbon  and 
hydrogen  than  to  be  built  up. 

Thepr oduct ion  of  ethylene  in  these  experiments  was  very 
desirable,  because,  it  was  noticed  that  wherever  the  percentage 
of  ethylene  in  the  outgoing  gas,  was  around  three  or  four  percent, 
the  yields  of  the  higher  boiling  compounds  were  appreciably  in- 
creased. In  general,  it  was  found,  that  ethylene  decomposed 


. 


. . . ■*’  ' 

. 


■ 


. 


< 

, 


. 

. 


* ' 

, 

- • 1 • 


79 


into  a mixture  of  ethane  and  methane  in  the  neighborhood  of  500°C. 
Above  500°C  the  ethane  content  gradually  decreased  and  around 
650°C  disappeared  entirely  with  a resultant  increase  in  methane. 
Ethylene  seems  to  be  able  to  decompose  in  several  ways,  which  no 
doubt  explains  its  usefulness  in  the  building  up  process. 

Bone  and  Coward  concluded  that  the  primary  action  of  heat 
on  ethylene  is  to  eliminate  hydrogen.  The  residue  : CH  thus 
formed  may  decompose  or  be  hydrogenated  to  methane,  or  it  may 
unite<  with  another  such  residue  to  form  acetylene.  Rollings 
& Cobb  found  that  at  lower  temperatures,  around  800°C  it  decomposed 
into  methane  and  acetylene,  while  at  higher  temperatures  it  went 
into  methane  and  hydrogen. 

In  some  of  these  experiments  as  high  as  15$  of  the  waste 
gas  was  found  to  be  ethane.  It  was  also  found  that  very  little 
ethane  was  formed  below  600°C  and  that  it  w as  all  practically  de- 
composed at  700  to  725°C , except  in  the  presence  of  steam, which 
seemed  to  stabilize  it  at  slightly  higher  temperatures.  These 
temperatures  are  far  lower  than  found  by  Rollings  and  Cobb  who 
found  that  the  decomposition  of  ethane  was  rapid, but  not  complete 
in  46  seconds  at  800°C . At  1100°C  only  88  percent  was  decomposed, 
the  chief  products  being  ethylene  and  methane.  Ho  doubt  the  mole- 
cular decomposition  of  ethane  played  an  important  part  in  these 

25 

experiments.  According  to  J.J.  Thomson  , such  residues  as  i CH 
: CHg  and  . CHg  may  exist  momentarily  in  the  free  state.  The 
four  possibilities  open  to  the  residue  : CHg  are:  (l)  to  form 
ethylene  by  contact  with  another  similar  residue;  (2)  to  break 
down  into  carbon  and  hydrogen;  (3)  to  be  hydrogenated  to  methane; 


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80. 


(4)  or  attach  to  some  heavier  molecular  formation,  - a partial  de- 
composition, of  the  benzene  necleus  or  homologues. 

The  above  is  only  a partial  list  of  the  gaseous  consti- 
tuents in  the  furnace  atmosphere  during  decomposition, undoubtedly 
many  more  complex  groups  or  radicles  from  the  higher  boiling 
compounds  exerted  an  important  influence  on  the  process. 

A few  of  the  liquid  hydrocarbons  obtained  in  this  investi- 
gation are  listed  below.  All  were  definitely  identified  by  the  com 
men  tests  and  known  derivatives  were  made.  These  results  are 
qualitative  only,  as  no  definite  scheme  of  separation  has  been 
worked  out,  Mr.  Malecki  is  working  on  the  solid  and  liquid  pro- 
ducts obtained  in  this  investigat ion , and  his  methods  of  separ- 
ation, purification  and  irienti fication  will  be  given  in  his 
graduation  thesis  in  February  1922. 

N-Hexane  (B.P.68)  wa.s  obtained  in  very  small  quantities  along 
with  another  highly  unsaturated  hydrocarbon, whi ch  boiled  around 
the  same  temperature , in  the  runs  made  under  high  pressure  with 
ethylene . 

Cyclo  hexane  (B.P.80)  was  also  obtained  in  very  small  quantities 
in  the  same  runs. 

Benzene  (B.P.80. 5)  was  recovered  and  purified  from  several  runs. 
The  largest  yield  of  the  crude  product  obtained  was  approxi- 
mately 93.0  percent  of  the  possible  theoretical. 

Toluene  (B.P.  110 ) was  obtained  in  many  of  the  runs  over  char- 
coal. the  maximum  yield  of  the  crude  product  being  about  66.0  per- 
cent theoretical.  Very  little  work  has  been  done  on  the  higher 




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81. 


boiling  compounds  listed  in  table  19,  Only  three  having  been 
definitely  identified. 

Pitolyls  (mixed,  3.P.  about  275C)  were  identified. 

A-Methylnaphthalene  (B .P.240-242 ) has  also  been  purified;  while 
diphenyl ethane  (B. P.286)  has  been  obtained  in  small  amounts. 

The  solids  synthesised  in  this  investigation  are  also  ex- 
remely  complex.  In  a single  series  of  runs  the  high  boiling  con- 
stituents were  very  similar  hn  each  run,  but  in  different  series 
the  variation  was  marked.  It  was  quite  noticeable  that  when  using 
cobalt  and  manganese,  the  high  boiling  oils  had  a larger  percent- 
age of  solids  containing  anthracene.  Only  a very  few  of  these 
solid  compounds  have  been  purified,  a partial  list  follows: 

Diphenyl  (M.P.700)  was  obtained  in  considerable  quantities  in 
the  fraction  boiling  from  240-255°C.  On  standing  it  settled 
out  as  a white  solid.  This  product  would  come  from  tfoo  benzene 
molecules  with  the  liberation  of  hydrogen.  Durfton  and  Cobb 
have  proven  this  to  be  a reversible  reaction  by  passing  diphenyl 
and  hydrogen  through  a hot  siliea  tube  and  producing  benzene. 

Napthalene  (M.P.8Q0)  was  obtained  in  considerable  quantities,  as 
closely  as  could  be  determined,  in  approximately  4%  yields  on  the 
original  xylene  used.  In  view  of  the  conflicting  reports  in  the 
literature  concerning  the  formation  of  napthalene  at  low  temper- 
ature and  from  similar  liquids,  toluene  especially,  particular 
care  was  taken  in  the  identification  of  this  compound.  The 
presence  of  stilbene  may  give  a clue  to  its  formation. 


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82 


Stilbene  (M.P.  124°)  was  found  in  very  small  quantities,  apparent- 
ly it  had  been  mostly  condensed  to  napthalene. 

Methyl  Anthracene  (M.P.  198-200)  mixtures  of  the  A and  B compounds 
have  been  obtained. 

P-Diphenyl  Benzene  (M.P.  207)  has  also  been  identified. 

Anthracene  (M.P.  214-216)  has  been  purified. 

2.3  Dimethyl -Anthracene  has  been  purified,  and  the  other  forms 
are  also  present,  but  so  far  have  not  been  purified.  A mixed 
quantity  of  trimethyl  anthracene  is  also  present. 

Chrysene  (^.P.  248-50)  was  obtained  in  small  amounts  in  the  runs, 
with  ethylene  and  xylene,  under  high  pressures. 

Another  compound  which  has  been  separated,  is  very  similar 
to  asphaltenes  in  its  appearance , behavior  toward  solvents , espec- 
ially ether  and  hexane,  and  contains  sulphur.  It  is  not  easy 
to  determine  where  the  sulfur  came  from  to  enter  the  reaction, 
unless  it  was  obtained  from  the  charcoal,  metals  or  pumice1  stone. 

No  doubt  many  more  compounds  may  be  identified  but  the 
above  list  is  sufficient  to  demonstrate  the  extremely  complex 
molecular  formations  which  were  produced  in  these  experiments. 

It  is  evident  that  any  compound  that  can  be  synthesised 
from  benzene  or  toluene  by  pyrogenetic  decomposition,  under 
similar  conditions  to  the  above,  can  also  be  produced  from  xylene, 
because  it  is  capable  of  being  broken  down  into  similar  groups 
or  atoms  or  molecular  formations. 


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83 


IV.  SUMMARY 

Some  of  the  most  important  facts  established  by  the  fore- 
going investigation  are  given  in  the  following  summary. 

(1)  Mixed  xylenes,  under  favorable  conditions  of  temper- 
ature, contact  surfaces  and  pressure,  can  be  decomposed  into  tolu- 
ene or  benzene.  The  gaseous  atmosphere  most  favorable  to  this 
reaction  is  either  methane  or  hydrogen. 

(2)  Under  identical  conditions  of  temperature,  contact 
surfaces  and  pressure,  xylenes  can  be  built  up  to  form  naptha- 
lene,  anthracene,  and  the  methyl  derivatives  of  both.  The  gaseous 
atmosphere  favoring  the  reaction  is  preferably  ethylene  or 
other  unsaturated  gaseous  hydrocarbons. 

(3)  Metallic  ^xide  surfaces,  especially  after  being 
slightly  reduced  at  temperatures  where  they  decompose  xylene 
freely,  influence  to  complete  decomposition  of  the  hydrocarbons 
to  hydrogen,  methane  and  carbon. 

(4)  The  reduced  metallic  surfaces,  or  freshly  oxidized 
surfaces  at  the  same  temperature  is  much  less  reactive,  and  in- 
fluences to  partial  decomposition. 

(5)  Non-metal li c substances  such  as  charcoal , pumice , or 
refractory  material  at  like  temperatures  tend  to  decompose  xy- 
lenes into  unsaturated  and  higher  boiling  compounds.  The  decom- 
position to  carbon  is  materially  lessened. 

(6)  The  gaseous  atmosphere  in  which  pyrogenic  decomposi- 
tion takes  place  exerts  an  extremely  important  influence  on  the 
products  of  decomposition.  Gases  like  methane  and  nitrogen  between 


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84 


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temperatures  of  600  to  700  C have  only  a mechanical  action. 
Ethylene,  acetylene,  hydrogen  and  ethane  between  the  same  temper- 
atures have  also  a mechanical  bearing  on  the  end  products.  Their 
all-important  action,  however,  is  chemical,  tending  to  produce 
high-boiling  compounds;  ethylene,  acetylene  and  ethane  were  found 
to  be  entirely  decomposed  at  temperatures  above  725°C. 

(7)  By  the  deliberate  control  of  the  gaseous  atmosphere 
under  which  decomposition  takes  place,  the  yields  of  the  desired 
products  can  be  greatly  increased. 

(8)  Steam,  air  and  carbon  dioxide  poison  or  deaden  acti- 
vated surfaces,  in  such  a way  that  they  appear  to  stabilize  li- 
quid hydrocarbons. 

(9)  Contact  surfaces  are  very  important  in  hydrogenati on 
and  dehydrogenation  of  aromatic  hydrocarbons. 

(3D)  Pressure  under  some  conditions  favors  molecular  con- 
densation that  is,  if  the  pressure  is  made  up  of  unsaturated 
gases.  In  other  cases  it  caused,  where  the  pressure  was  made  up 
by  hydrogen,  the  decomposition  of  the  heavier  molecules  into  the 
single  ring  compounds.  Pressure  in  all  cases  lessened  the 
percentage  of  unsaturated  hydrocarbons  in  the  final  products. 

(ll)  Decomposition  of  hydrocarbons  increases  with  rise  in 
temperature.  The  larger  molecules  being  less  stable  than  the 
smaller  ones  at  temperatures  above  700°C.  The  lower  the  tempera- 
ture at  which  decomposition  takes  place  the  more  economical  the 
reaction.  Lower  temperatures  can  be  used  in  the  presence  of 
activated  surfaced. 

(12)  Practically  all  of  these  reactions  are  reversible. 


. 

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85. 


BIBLIOGRAPHY 

1.  "Application  of  dynamics  to  Physics  and  Chemistry" 

2.  Bandcroft,  W.  "Applied  Colloid  Chemistry". 

3.  Sabatier  "La  Catalyse  en  Chimie  Organique". 

4.  Armstrong, H.E.  Brit .Assoc .Reports  1885,962. 

5.  Langmuir, Irving,  J.A.C.S.1916 ,38,2221 . ,191? ,39 ,1848. ,1918,40,1361 

6.  Harkins,  W.D. , J.A.C.S.,  1917,  39,  541. 

7.  Bertholet,  M.  AEIT  ChemPhys.  Ser  . 4 , t . 9 , 1866  .pp  445-483 

" » " " 4 , t .12,1867, pp  5-69 

" " " " 4, t .16, 1869, pp  143-187 

8.  Zanetti,  J.E.,  and  Kendall  M.,  J.Ind.and  Eng.Chem.Vol  .13f'3 

March  1921-pp  208-211 

9.  Zanette,  J.E.,  and  Egloff,  G.  J.Ind.  and  Eng.Chem, 9 ,pp350 , 1917 

10.  Ferko.Paul,  Ber .Deut . Cehm.Gesell , Jahrg.29,  Bd3,pp  660-4 

11.  Haber,  E.  Ber  Deut .Chem.Gesell .Jahrg.29 , Bd3. 

12.  McKee  G.W.  , Jour.  Soc.Chem.  Ind.  Vol.  23 , 1904 , pp403-4 

13.  Ipatieff,  V.H.,  J. Russ . Chem.Phys. Soc . 39 ,pp. 681 , 1907 

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15.  S^nith,  0.  and  Lewcock,  W.  ,J.  Chem.Soc.Vol  .101,pt2  ,pp  1453-59 

16.  R i 1 1 iiia  n , W.  5*.  , Dutton,  C.B.  , and  Dean  ,E.W.  , Bureau  of  Mines, Bull  114 
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18.  Cobb,J.W.  and  Dufton,S.4 . ,The  Gas  World, Vol .72 , 1920, pp  485 

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24.  Bone  and  Coward,  J.C.S.,  1908,  93,  1917 

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86 


VI.  VITA 

The  writer  of  this  thesis  received  his  early  education  in 
the  grade  school  at  Leskard,  and  high  school  at  Bowmanville,  Ontario 
Canada.  He  graduated  from  McMaster  University,  Toronto,  in  June 
1915,  with  the  degree  of  Bachelor  of  arts,  in  the  honor  science 
course.  In  September,  of  that  year,  he  received  the  degree  of 
Master  of  Science  from  the  same  University. 

After  graduation  he  entered  war  munition  work.  Prom  Sept. 
1915  to  March  1916  analysing  high  explosives  at  the  plant  of  The 
Canadian  Explosives  Ltd.,  Montreal.  Prom  March  1916  to  IT ov ember 
of  the  same  year  analysing  9.2  inch  sheel  steel,  at  the  plant  of 
The  Canada  Cement  Co ., Montreal . During  November  he  was  at  the  plant 
of  The  Armstrong-Whithworth  Co . .Longui el , Quebec , analysing  tool 
steel.  Prom  December  1916  to  October  1917  he  was  with  The  British 
Munitions  Board,  stationed  at  the  acetone  plant,  of  The  Canadian 
Electro  Products  Co.,  Shawinigan  Palls,  Quebec. 

Since  October  1917  he  has  been  at  the  University  of 
Illinois  doing  graduate  work.  While  here  he  has  held  the  follow- 
ing positions  in  the  Department  of  Chemistry.  October  1917  to  Feb- 
ruary 1918,  graduate  Assistant;  and  from  February  1918  to  the 
present  time,  half-time  assistant. 


